Evaluation of DISORDER: Retrospective Image Motion Correction for Volumetric Brain MRI in a Pediatric Setting

BACKGROUND AND PURPOSE:Head motion causes image degradation in brain MR imaging examinations, negatively impacting image quality, especially in pediatric populations. Here, we used a retrospective motion correction technique in children and assessed image quality improvement for 3D MR imaging acquisitions.MATERIALS AND METHODS:We prospectively acquired brain MR imaging at 3T using 3D sequences, T1-weighted MPRAGE, T2-weighted TSE, and FLAIR in 32 unsedated children, including 7 with epilepsy (age range, 2–18 years). We implemented a novel motion correction technique through a modification of k-space data acquisition: Distributed and Incoherent Sample Orders for Reconstruction Deblurring by using Encoding Redundancy (DISORDER). For each participant and technique, we obtained 3 reconstructions as acquired (Aq), after DISORDER motion correction (Di), and Di with additional outlier rejection (DiOut). We analyzed 288 images quantitatively, measuring 2 objective no-reference image quality metrics: gradient entropy (GE) and MPRAGE white matter (WM) homogeneity. As a qualitative metric, we presented blinded and randomized images to 2 expert neuroradiologists who scored them for clinical readability.RESULTS:Both image quality metrics improved after motion correction for all modalities, and improvement correlated with the amount of intrascan motion. Neuroradiologists also considered the motion corrected images as of higher quality (Wilcoxon z = −3.164 for MPRAGE; z = −2.066 for TSE; z = −2.645 for FLAIR; all P < .05).CONCLUSIONS:Retrospective image motion correction with DISORDER increased image quality both from an objective and qualitative perspective. In 75% of sessions, at least 1 sequence was improved by this approach, indicating the benefit of this technique in unsedated children for both clinical and research environments.

Head motion is a common cause of image degradation in brain MR imaging. Motion artifacts negatively impact MR image quality and therefore radiologists’ capacity to read the images, ultimately affecting patient clinical care.¹ Motion artifacts are more common in noncompliant patients,² but even in compliant adults, intrascan movement is reported in at least 10% of cases.³ For children who require high-resolution MR images, obtaining optimal image quality can be challenging, owing to the requirement to stay still over long durations needed for acquisition.⁴ Sedation can be an option, but it carries higher risks, costs, and preparation and recovery time.⁵In conditions such as intractable focal epilepsy, identification of an epileptogenic lesion is clinically important to guide surgical treatment. However, these lesions can be visually subtle, particularly in children in whom subtle cortical dysplasias are more common.⁶ Dedicated epilepsy MR imaging protocols use high-resolution 3D sequences to allow better cortical definition and free reformatting of orientation but involve acquisition times in the order of minutes, so data collection becomes more sensitive to motion.⁷For children in particular, multiple strategies are available for minimizing motion during MR examinations. Collaboration with play specialists using mock scanners and training or projecting a cartoon are good approaches to reduce anxiety.^8,9 These tools are not always available in clinical radiology and, even with these strategies, motion can still be an issue.¹⁰ Different scanning approaches to correct for intrascan motion have been proposed. Broadly, prospective methods track head motion in real time and modify the acquisition directions accordingly.¹¹ These approaches are applicable to a wide range of sequences but require optical systems with external tracking markers, sometimes uncomfortable or impractical, and extra setup can ultimately result in longer examinations. Furthermore, these approaches may also not be robust to continuous motion.^11-13 Retrospective techniques have also been proposed, in some cases relying on imaging navigators that are not compatible with all standard sequences or contrasts.¹²Here, we use a more general retrospective motion correction technique: Distributed and Incoherent Sample Orders for Reconstruction Deblurring by using Encoding Redundancy (DISORDER). In this method, k-space samples are reordered to enable retrospective motion correction during image reconstruction.¹⁴ Our hypothesis is that DISORDER improves clinical MR imaging quality and readability. To assess its use for clinical sequences, we acquired a dedicated epilepsy MR imaging protocol in 32 children across a wide age range. We used both objective image quality metrics and expert neuroradiologist ratings to evaluate the outcome after motion correction.     

How Postdoctoral Research in Paul Greengard's Laboratory Shaped My Scientific Career,Although I Never Did Another Phosphorylation Assay

In this short review, I describe from personal experience how every step in the career of any scientist, no matter how disjointed and pragmatic each might seem at the time, will almost inevitably meld together, to help us all tackle novel projects. My postdoctoral research in Paul Greengard''s laboratory, where I investigated neurotransmitter-mediated phosphorylation of Synapsin I, was instrumental in my career progression, and Paul''s support was instrumental in my ability to make a leap into independent research.

When the Society for Neuroscience was soliciting articles for its new journal, I was a postdoctoral fellow in Paul Greengard''s laboratory, completing studies of neurotransmitter regulation of synapsin I phosphorylation. When Paul informed me that he been invited to contribute a paper, we knew it would be risky thing to volunteer one''s precious data because this was an untested journal. But it came at a good time because I was about to leave the laboratory and had data that complemented my recently accepted paper demonstrating phosphorylation of the presynaptic protein Synapsin I (which we called Protein I at the time) by a neurotransmitter (Dolphin and Greengard, 1981b). So I was very happy to publish in the initial volume of the Journal of Neuroscience, which was to be the first of my 17 papers so far in the journal. The data published in 1981 extended my work on serotonin-mediated phosphorylation and also demonstrated phosphorylation by another class of neuromodulator, acting at adenosine receptors (Dolphin and Greengard, 1981a). It was such a pleasure for me to reread that paper, as it brought back many memories of life in the Greengard laboratory, together with colleagues and friends, including Pietro De Camilli, Angus Nairn, Wieland Huttner, Clive Palfrey, Eric Nestler, Suzanne Lohmann, Ulrich Walter, Howard Schulman, Mary Kennedy, and many others.My interest in intracellular signaling pathways activated by neurotransmitters began when I was an undergraduate student in Biochemistry; I wrote a dissertation on cyclic AMP in prokaryotes and eukaryotes, and then conducted an undergraduate research project examining glycine as a neurotransmitter, using spinal cord synaptosomes as an experimental preparation. This interest propelled me toward Parkinson''s disease research as a graduate student in the laboratory of the neurologist David Marsden at the Institute of Psychiatry in London, where I examined the importance of dopaminergic and noradrenergic pathways in animal models of Parkinson''s disease. I then wrote to Paul Greengard, asking to do postdoctoral research under his mentorship, because I knew I needed more basic training in cell signaling pathways, since my PhD environment had been very focused on translational and clinical research. I could not think of anywhere better than Paul''s laboratory because of his seminal work on cyclic nucleotide signaling pathways (Beam and Greengard, 1976). He said his laboratory was full, but agreed to take me in a year''s time, subject to interview. Fortunately, I had also obtained a UK Medical Research Council French exchange fellowship to work in the laboratory of Joel Bockaert, at College de France in Paris, where I studied the coupling between β-adrenergic receptors and adenylate cyclase. This valuable experience cemented my desire to continue research in this area and work with Paul Greengard. Thus it was that Paul, on a visit to Paris, invited me to be interviewed in his hotel room. I was on my guard when I knocked on the door, and a voice called out to come in. As I entered, I could see nothing but a large bed, but I soon located Paul lying flat on the floor beyond; he explained it was because of his chronic back problem. I perched on the bed, and tried to answer his searching scientific questions. I later realized that Paul lay on the floor at every opportunity, often in our laboratory meetings and indeed during other interviews (Nestler, 2019).When I arrived in Paul''s laboratory then at Yale, in the summer of 1978, the protein Synapsin I had recently been identified as a major presynaptic phosphoprotein (Ueda and Greengard, 1977). It was then called “Protein 1” because it stood out as the main polypeptide in synaptosomes that was phosphorylated in both a cAMP- and a Ca²⁺-dependent manner (Sieghart et al., 1979). However, no neurotransmitters had yet been found to influence the phosphorylation of Synapsin I, and to identify such a pathway seemed to be the holy grail at the time. Paul''s world view of multiple signaling cascades terminating in the phosphorylation of many different target proteins, that would underlie long-term synaptic events, was often at odds with the then prevailing view of ion channel biologists, that neurotransmission was mediated by fast neurotransmitters acting on ion channels, a process in which there was no need to consider neurochemical mechanisms. Eric Kandel (from an electrophysiological standpoint), and Paul, from the basis of biochemical pathways, were both key to the acceptance of the view that a multitude of biochemical pathways must play a role in longer term events. Indeed, Paul was collaborating with Eric Kandel''s laboratory at that time to elucidate whether a phosphorylation cascade mediated the effects of serotonin (5-HT) in Aplysia, and many of us in the laboratory were very influenced by these elegant studies, combining, as they did, electrophysiology and biochemical approaches (Castellucci et al., 1980, 1982).Paul suggested that my project should be to examine whether neurotransmitters could change the state of phosphorylation of Synapsin I in the brain, but he left it entirely to me what tissue I should use for my study. There were ∼25 postdocs and students in his laboratory at the time, and so I had a lot of help and advice, although Paul was the opposite of a micro-manager. Influenced both by the work of Eric Kandel and that of my previous mentor Joel Bockaert (Enjalbert et al., 1978), I decided that serotonin would be a good neurotransmitter to study. Taking inspiration from the work of George Aghajanian, also a professor in the Pharmacology Department at Yale, whose studies had revealed the effects of serotonin on many types of neuron (Aghajanian et al., 1990), I chose to examine the tiny facial nucleus in the brainstem, since Aghajanian had extensively examined the electrophysiological properties of this nucleus, as well as its ultrastructure (Aghajanian and McCall, 1980). His work indicated the facial nucleus had no interneurons, and therefore I thought it might lead to a more homogeneous phosphorylation response than many other brain areas. Indeed, serotonin did result in an increase in phosphorylation of Synapsin I in this preparation, but I initially found that the effects were small and very variable (Fig. 1, left). This was disappointing, and I remember blaming myself for being a cack-handed experimenter.Open in a separate windowFigure 1.Phosphorylation of Synapsin I by actions at serotonin and adenosine receptors. Stimulation of Synapsin I (then called Protein I) phosphorylation with serotonin in the presence and absence of IBMX (left) (from Dolphin and Greengard, 1981b, our Fig. 2) or 2-choloroadenosine (right) (from Dolphin and Greengard, 1981a, our Fig. 4). The “back phosphorylation” method was used, in which ³²P-ATP together with catalytic subunit of protein kinase A were used to phosphorylate residual nonphosphorylated sites on Synapsin I.A breakthrough came indirectly through family tragedy; my father died in 1979, and I returned to England for the funeral. Fortuitously, I also decided to investigate potential future positions in the UK, and visited Leslie Iversen''s Medical Research Council unit in Cambridge. While there, I showed my underwhelming phosphorylation data to John Dowling, who was on sabbatical in the unit at the time, working on dopamine-sensitive adenylate cyclase activity in the retina (Watling et al., 1979). I asked his advice and remember clearly that he suggested adding a low concentration of a phosphodiesterase inhibitor to the slices to potentiate the cAMP response to serotonin. On my return, I duly added isobutyl-methyl-xanthine (IBMX) to the facial nucleus slices, and the responses became much more robust (Dolphin and Greengard, 1981b) (Fig. 1, left). Similarly, Eric Nestler also found that dopamine and depolarization increased the phosphorylation of Synapsin I in superior cervical ganglion neurons (Nestler and Greengard, 1980).Something I could not understand in my data was that the serotonin-mediated phosphorylation of Synapsin I was Ca²⁺-dependent, whereas the phosphorylation mediated by stimulation of an adenosine receptor was not. This was the main topic of my follow-up paper in the first volume of Journal of Neuroscience (Dolphin and Greengard, 1981a) (Fig. 1, right). Everyone in the laboratory remembers that writing papers with Paul was exhausting, as we considered multiple versions of every sentence, and these were written and rewritten in pencil with many erasures. But I can still hear his voice in every phrase of this Journal of Neuroscience paper, and it remains a pleasure to reread each well-considered argument, for which I take absolutely no credit.In the Discussion, many possibilities are suggested to explain the surprising Ca²⁺ dependence of the serotonin-stimulated phosphorylation, and these points remain relevant, even now. For example, we point out that, in Aplysia neurons, serotonin stimulated a presynaptic adenylate cyclase, and this increased the influx of Ca²⁺ (Shimahara and Tauc, 1977; Klein and Kandel, 1978). We suggested that both processes might contribute to presynaptic Synapsin I phosphorylation. I also wonder now if we were seeing a combined effect of 5HT3 receptor activation, allowing Ca²⁺ entry, and subsequent Ca²⁺-calmodulin (CaM) kinase-dependent phosphorylation of Synapsin I, as well as activation of presynaptic serotonergic GPCRs that directly stimulated adenylate cyclase. Of course, the existence of 5HT3 receptors, which are Ca²⁺-permeable ion channels, and the many subtypes of G-protein-coupled 5-HT receptors was unknown at the time (Raymond et al., 2001).My study of neurotransmitter-dependent phosphorylation of Synapsin I was cut short because of family problems that called me back to the UK. But work on Synapsin I simultaneously involved many others in Paul''s laboratory, so research on its subcellular localization and function continued apace. For example, Wieland Huttner and Mary Kennedy both contributed to unraveling the process of Ca²⁺-dependent phosphorylation of Synapsin I (Huttner et al., 1981; Kennedy and Greengard, 1981). Indeed, cAMP-dependent protein kinase and CaM kinase both phosphorylated the same site on Synapsin I, and CaM kinase also phosphorylated additional sites (Huttner et al., 1981). Pietro De Camilli showed in elegant immuno-electron microscopic studies that Synapsin I was a cytoplasmic protein that was associated with synaptic vesicles (De Camilli et al., 1983). To date, there are over 2000 studies involving Synapsin I listed in PubMed, identifying its roles in synaptic function and pathology. These include many from Paul''s own laboratory, continuing throughout his career (Hilfiker et al., 2005; Venton et al., 2006).When I returned to UK, I had the good fortune to obtain a staff position at the Medical Research Council''s National Institute of Medical Research (NIMR) at Mill Hill in London. This was an institution that Paul knew well, since he had spent a postdoctoral period in Wilhelm Feldberg''s department at NIMR in the 1950s, recording from sympathetic nerve fibers. I find it fascinating that Paul was already interested in phosphorylation even then (Greengard and Straub, 1959a, 1959b). My post came about entirely through Paul''s suggestion and generosity: he wrote to Arnold Burgen, then the Director of the Institute, whom he must have known from his work on cholinergic transmission. Suddenly and miraculously, I was offered a job, during a period when Margaret Thatcher was Prime Minister, the UK was in a deep recession, and academic positions were few and far between.Before arriving, I knew very little about NIMR, and was thrilled to be appointed into the same Division of Neurophysiology and Neuropharmacology, which had previously housed the Yale triumvirate of Paul Greengard, Murdoch Ritchie, and Bill Douglas, and which currently contained an eclectic and exciting mix of groups studying pain, hearing, epilepsy, and hippocampal LTP. Wilhelm Feldberg also still had a laboratory there, and used to call me Delphine. I was, however, supernumerary, and given a small cupboard to work in, and an even smaller research consumables budget. In that environment, since I had become intrigued by presynaptic events, I decided to examine neurotransmitter release, and its modulation by activation of presynaptic receptors, including those activated by adenosine agonists, building on my knowledge of the very robust response of Synapsin I phosphorylation (Dolphin, 1983; Dolphin and Archer, 1983). I also rapidly developed an enjoyable collaboration with Tim Bliss and members of his group, including Mick Errington, working with them to measure field potentials and examine glutamate release from the dentate gyrus during the induction of LTP (Dolphin et al., 1982).Studying the regulation of neurotransmitter release naturally led me to further questions about regulation of the Ca²⁺ influx that triggers this release, but this was not something I could directly address at NIMR. Although it did not feel like it at the time, it was fortuitous that the rules for obtaining tenure changed while I was there, meaning that to apply for tenure I would have to reapply for my position and then remain untenured for another 5 years. Many of the affected staff started to look for university posts, and I was offered a lectureship at St. George''s Hospital Medical School, in the Department of Pharmacology. The interview went well, apart from being asked if I intended to have children, and I moved there in 1983, hoping again to pivot my research in a new direction. At that time, the Department was almost entirely populated by electrophysiologists, including the Head of Department, John Kelly, together with Vincenzo Crunelli, Mark Meyer, and Tom Bolton.In this environment, it would be feasible for me to study voltage-gated calcium channels and their modulation by neurotransmitters, and how this related to neurotransmitter release. Ironically, while I was at Yale, Richard Tsien was on the faculty in the Physiology department, doing beautiful work on cardiac electrophysiology, leading up to an understanding of how cAMP modulates cardiac calcium channels, and the existence of additional calcium channels in neurons (Bean et al., 1984; Nowycky et al., 1985). However, my main memory of Dick Tsien at the time was that he adjudicated on my Yale postdoctoral fellowship application. When I started investigating calcium channels, I very belatedly wished I had concentrated better during Physiology seminars at Yale, to take advantage of their wealth of knowledge. Nevertheless, through the enormous generosity particularly of John Kelly at St. George''s, I was able to learn how to record calcium currents in DRG neurons, which had already been established as a model to study presynaptic events (Dunlap and Fischbach, 1978). Together with my first postdoctoral research assistant and great friend, Rod Scott, we started to apply the same techniques to examine the mechanism of modulation of action potentials and calcium currents in these neurons by neurotransmitters, where we showed inhibition, particularly by activation of GABA-B and adenosine receptors (Dolphin et al., 1986).Tools were initially lacking to study the role of G proteins in the modulation of calcium channels and neurotransmitter release, but this changed for me when I visited Pietro De Camilli in Milan and attended the Fifth International Conference on Cyclic Nucleotides and Protein Phosphorylation, in July 1983. There I heard about the use of pertussis toxin to distinguish between different GTP binding protein mechanisms. Although it was not yet available commercially, I managed to locate a local source of pertussis toxin (entailing rather scary visits to the UK government Center for Applied Microbiology & Research at Porton Down, where research on dangerous toxins and pathogens was conducted). Using both pertussis toxin and nonhydrolyzable guanine nucleotide analogs (including photoactivatable forms, made by John Wootton and David Trentham at NIMR), we then investigated the involvement of pertussis toxin-sensitive G proteins in the modulation of both glutamate release (Dolphin and Prestwich, 1985) and calcium currents (Dolphin et al., 1986; Scott and Dolphin, 1986; Dolphin et al., 1988).One of the next big scientific questions was to examine the same modulatory processes using the calcium channel subunits that were being cloned at that time by several groups (Tanabe et al., 1987; Ellis et al., 1988; De Jongh et al., 1990; Mori et al., 1991; Starr et al., 1991; Williams et al., 1992). In 1989, I was asked to apply for the Chair of Pharmacology at the Royal Free Hospital School of Medicine in London, and there I reoriented our efforts to examine the role of specific calcium channel subunits in the modulation of native and cloned calcium currents by G proteins. In our work, we concentrated initially on the role of the calcium channel β subunits (Berrow et al., 1995). We then uncovered an essential role for the N-terminus of Ca_V2 calcium channels in their G-protein modulation (Page et al., 1998; Canti et al., 1999), and we demonstrated the importance of calcium channel β subunits in the G-protein modulation of Ca_V2.2 channels (Meir et al., 2000; Leroy et al., 2005), and also in PI3 kinase-mediated calcium channel modulation (Viard et al., 2004).At that time, very little work had been done on the role of the intriguing α₂δ subunits of calcium channels, whose topology and function were initially unclear (Brickley et al., 1995; Gurnett et al., 1996). We started working on these proteins through another fortunate encounter. When the Royal Free School of Medicine was merged with University College London (UCL), I was asked to move to the UCL Gower Street campus in 1997, primarily to free up my space for Professor Geoff Burnstock, who had relinquished his role as Head of Department of Anatomy at UCL. There, I had the good fortune to collaborate with Michele Rees in the Pediatrics Department, on the molecular basis for the Ducky mouse mutation, that causes absence epilepsy and ataxia. The mutation turned out to be in a calcium channel auxiliary subunit gene, Cacna2d2, encoding α₂δ−2 (Barclay et al., 2001). This work fortuitously led us on to an extended series of studies on the biochemistry, physiology, and pharmacology of the α₂δ subunit family, about which little was then known. These investigations allowed me to combine my interests in biochemistry, from my undergraduate years, with all the many other techniques we have embraced, including electrophysiology. Among our findings were that the von Willebrand factor domain of α₂δ subunits is essential for their ability to augment calcium currents (Canti et al., 2005; Hoppa et al., 2012; Dahimene et al., 2018), that α₂δ proteins are anchored to the plasma membrane via a glycosyl-phosphatidyl inositol linkage rather by a transmembrane domain (Davies et al., 2010), that the α₂δ subunits increase trafficking of calcium channels to the cell surface (Cassidy et al., 2014), and that proteolytic cleavage of α₂δ into α₂ and δ is an essential molecular switch for the augmentation of calcium currents and transmitter release (Kadurin et al., 2016; Ferron et al., 2018).Other studies, including work from our own laboratory, found that α₂δ−1 mRNA and protein are strongly upregulated in DRG neurons in rodent models of neuropathic pain (Luo et al., 2001; Newton et al., 2001; Bauer et al., 2009). Furthermore, α₂δ−1 is the main receptor for the antiepileptic drug gabapentin, which is also of therapeutic benefit in neuropathic pain (Gee et al., 1996). We contributed to showing that their binding to α₂δ−1 is essential for the action of gabapentinoids to alleviate neuropathic pain (Field et al., 2006). Since α₂δ proteins are auxiliary subunits, the molecular mechanism of action of these drugs in neuropathic pain was not immediately obvious, until we showed that gabapentinoids reduced calcium currents chronically, but not acutely, through an inhibitory effect on α₂δ trafficking, both in vitro (Hendrich et al., 2008; Tran-Van-Minh and Dolphin, 2010) and in vivo (Bauer et al., 2009). We then found, by making a functional extracellularly tagged version of Ca_V2.2, that as a consequence, gabapentin also reduced the trafficking and cell surface expression of the channel itself (Cassidy et al., 2014). A knock-in mouse containing this tagged Ca_V2.2 is now allowing us to identify that α₂δ−1 KO also reduces the cell surface localization of Ca_V2.2 in DRGs and their presynaptic terminals in vivo (Nieto-Rostro et al., 2018).The molecular mechanisms involved in the development and maintenance of neuropathic pain are the subject of research of many groups (for review, see Sexton et al., 2018; Alsaloum et al., 2020; Halievski et al., 2020). As a result of orienting our research toward the involvement of calcium channels in neuropathic pain, I encountered another unexpected advantage of moving to UCL. We have been able to benefit enormously from the knowledge and advice of the many experts in pain who work there, including John Wood, Tony Dickenson, and Maria Fitzgerald. It is remarkable that, during my time at UCL, threads from my past have been picked up and helped to shape my work. Indeed, we have collaborated extensively with Tony Dickenson, who was one of the other nontenured staff scientists who left NIMR at the same time as me, and who then obtained a lectureship directly at UCL (Bauer et al., 2009; Patel et al., 2013). Similarly, in an extension of the Greengard family, we had a valuable collaboration with Tim Ryan, who has also worked extensively with Paul Greengard''s laboratory, particularly on the role of Synapsins in vesicular release (Ryan et al., 1996; Chi et al., 2003). With Tim, we studied the role of α₂δ proteins in presynaptic Ca²⁺ entry and vesicular release (Hoppa et al., 2012), and this led us on to further examining the role of proteolytic cleavage of α₂δ in these processes (Kadurin et al., 2016; Ferron et al., 2018).I was honored to speak at Paul''s 80th birthday celebration, and then also to attend his 90th birthday symposium, both held at Rockefeller University, where I was very happy to meet up with so many previous colleagues (Fig. 2). At the latter meeting, I also had the privilege of being able to tell Paul of my election to the Royal Society, and to thank him for his support; and I could see his real pleasure in this news. Although I have never worked directly on Synapsins since leaving Paul''s laboratory, from these and other meetings, I have of course retained a keen interest in Paul''s wide-ranging research, maintained until his death at age 93 in 2019. His work unraveling the enormous complexity of the many pathways involving neuronal protein phosphorylation, and their physiological and pathologic roles (Hilfiker et al., 1999; Svenningsson et al., 2004; Brichta and Greengard, 2014), contributed to his being awarded the Nobel Prize in 2000, together with Arvid Carlsson and Eric Kandel.Open in a separate windowFigure 2.Eric Nestler, Paul Greengard, Annette Dolphin; December 11, 2015 at Paul''s 90th birthday celebration.For younger scientists, I have only a few messages. Like me, I hope you will find that all your scientific studies and experience will be of benefit in the long run, even if you change fields, and all your scientific mentors, colleagues, and friends will remain important throughout your career; but the value of chance, casual conversations, and fortuitous meetings cannot be overstated. Treasure them all.     

Impact on Health-Related Quality of Life of Induction Chemotherapy Compared With Concurrent Cisplatin and Radiation Therapy in Patients With Head and Neck Cancer

AimsOrgan preservation, an important goal in the treatment of head and neck squamous cell carcinoma (HNSCC), may include induction chemotherapy and cisplatin with radiation therapy (CRT). To our knowledge, no reports have directly compared the impact of induction chemotherapy with that of CRT on health-related quality of life (HRQOL).Materials and methodsIn a phase II trial, we assessed the HRQOL of patients treated with induction chemotherapy followed by CRT. Eligible patients had stage III–IV HNSCC. HRQOL questionnaires were administered at baseline, the end of induction (EOI), the end of CRT (EOCRT) and after CRT. Functional Assessment of Cancer Therapy (FACT version 4) assessed HRQOL. We carried out a comparison of changes in HRQOL from baseline to EOI and from EOI to EOCRT. This trial is registered with ClinicalTrials.gov (NCT01566435).ResultsThirty patients were enrolled in the study. Most HRQOL questionnaires were completed (88%). The mean total FACT scores did not differ from baseline to EOI (general: 83.8 versus 79.1, P = 0.08; head and neck: 109.7 versus 105.8, P = 0.33; Total Outcome Index: 69.7 versus 62.3, P = 0.03; respectively, using P ≤ 0.01 to adjust for multiple simultaneous tests of differences). However, total FACT scores significantly worsened from EOI to EOCRT (79.1 versus 62.3, P = 0.01; 105.8 versus 74.2, P < 0.01; 62.3 versus 34.2, P = 0.01; respectively). Within domains, the head and neck cancer subscale score did not differ from baseline to EOI (median 28.5 versus 27.0, P = 0.69), but significantly worsened from EOI to EOCRT (27.0 versus 9.5, P < 0.01). Swallowing, oral pain and voice quality improved from baseline to EOI, but worsened from EOI to EOCRT. Physical and functional scores worsened from baseline to EOI and from EOI to EOCRT. The emotional well-being score improved from baseline to EOI but worsened from EOI to EOCRT.ConclusionsOverall, HRQOL did not significantly change from baseline to EOI but dramatically worsened from EOI to EOCRT.     

Measurement of brain lactate during visual stimulation using a long TE semi‐LASER sequence at 7 T

Estimation of metabolic changes during neuronal activation represents a challenge for in vivo MRS, especially for metabolites with low concentration and signal overlap, such as lactate. In this work, we aimed to evaluate the feasibility of detecting lactate during brain activation using a long (144 ms) semi‐LASER sequence at 7 T. spectra were acquired on healthy volunteers ( ) during a paradigm with 15 min of visual stimulation. Outer‐volume signals were further attenuated by the use of saturation slabs, and macromolecular signals in the vicinity of the inverted lactate peak were individually fitted with simulated Lorentzian peaks. All spectra were free of artefacts and highly reproducible across subjects. Lactate was accurately quantified with an average Cramér‐Rao lower bound of 8%. Statistically significant ( , one‐tailed ‐test) increases in lactate ( 10%) and glutamate ( 3%) levels during stimulation were detected in the visual cortex. Lactate and glutamate changes were consistent with previous measurements. We demonstrated that quantification of a clear and non‐contaminated lactate peak obtained with a long TE sequence has the potential of improving the accuracy of functional MRS studies targeting non‐oxidative reaction pathways.     

Pregnancy (im)possibilities: identifying factors that influence sexual minority women’s pregnancy desires

ABSTRACT

Sexual minority women (SMW) face both increased risk for unintended pregnancy and barriers to achieving wanted pregnancy, but little research investigates SMW’s pregnancy desires. To fill this gap, we conducted five focus groups and 11 in-depth interviews with 20-30-year-old SMW in three US cities. Findings highlight that the heteronormative pregnancy planning paradigm lacks salience for SMW. While some SMW clearly wish to avoid pregnancy, many others are unsure, and factors influencing this uncertainty include relationship context, anticipating logistical barriers, and discord between queer identity and pregnancy.     

Increasing the rate of the hydrogen evolution reaction in neutral water with protic buffer electrolytes

Electrocatalytic generation of H₂ is challenging in neutral pH water, where high catalytic currents for the hydrogen evolution reaction (HER) are particularly sensitive to the proton source and solution characteristics. A tris(hydroxymethyl)aminomethane (TRIS) solution at pH 7 with a [2Fe-2S]-metallopolymer electrocatalyst gave catalytic current densities around two orders of magnitude greater than either a more conventional sodium phosphate solution or a potassium chloride (KCl) electrolyte solution. For a planar polycrystalline Pt disk electrode, a TRIS solution at pH 7 increased the catalytic current densities for H₂ generation by 50 mA/cm² at current densities over 100 mA/cm² compared to a sodium phosphate solution. As a special feature of this study, TRIS is acting not only as the primary source of protons and the buffer of the pH, but the protonated TRIS ([TRIS-H]⁺) is also the sole cation of the electrolyte. A species that is simultaneously the proton source, buffer, and sole electrolyte is termed a protic buffer electrolyte (PBE). The structure–activity relationships of the TRIS PBE that increase the HER rate of the metallopolymer and platinum catalysts are discussed. These results suggest that appropriately designed PBEs can improve HER rates of any homogeneous or heterogeneous electrocatalyst system. General guidelines for selecting a PBE to improve the catalytic current density of HER systems are offered.

Molecular hydrogen (H₂), a clean-burning and energy-dense fuel source, has been widely discussed as an attractive way to store intermittent energy from solar and wind through water electrolysis (1, 2). Current commercial electrolyzers can be separated into two categories based on their operating pH. The first are acidic polymer electrolyte membrane electrolyzers that work best with rare and expensive platinum-based electrocatalysts for the hydrogen evolution reaction (HER) (3). The second are strongly alkaline electrolyzers that suffer from caustic basic reaction conditions (4). Neutral pH conditions with inexpensive catalysts composed of Earth-abundant elements are a target for practical solar-to-hydrogen fuel devices due to lower cost and fewer safety concerns (5), but achieving fast rates with mild overpotentials under neutral conditions remains a challenge (6–12). In the pH range from 5 to 9, the electrocatalytic activity of platinum (Pt) itself does not conform to the expected thermodynamic potential shift with pH dependence of −59 mV/pH (13). This is due to the low concentration of the hydronium ion in this pH range and a transition to water as the primary reactant, which has a higher thermodynamic requirement for hydrogen evolution (13). Studies of electrocatalysts using buffers to maintain the pH in this range and ionic salts such as potassium chloride (KCl) to provide ionic strength to ensure high solution conductivity have shown that the buffer can aid the HER activity, presumably by acting as a proton donor (6, 14–18). To extend the scope of water-soluble electrocatalysts, biopolymers and bioinspired metallopolymer catalysts have also been studied (7, 12, 17–26). Bren and coworkers recently reported particularly enlightening studies of the effects of buffer pK_a and structure on the mechanism of the hydrogen evolution reaction for cobalt minienzymes (17, 18).We recently reported a new metallopolymer catalyst system built around a customized [2Fe-2S] catalyst site with a bridging aryldithiolato ligand which exhibits remarkable catalytic activity, air stability, and chemical stability (21). The electrocatalytic mechanism of the [2Fe-2S] catalysts with aryldithiolato ligands is known from previous studies and these catalysts operate at rates of 10⁵ s⁻¹ and faster (27–30). The readily synthesized and water-soluble metallopolymer composed of tertiary amine side-chain groups, PDMAEMA-g-[2Fe-2S] (Fig. 1), approached the current density of Pt operating in neutral water under the same conditions and matched the Faradaic yield (97 ± 3%) (21). Although the detailed structural and mechanistic causality of these profound improvements for these metallopolymer electrocatalysts remain subjects of study, the nature of this molecular system is ideal for studying solution effects on the HER reaction at neutral pH for complexes that are normally insoluble in water. In the course of characterizing these electrocatalysts, solutions containing tris(hydroxymethyl)aminomethane (TRIS) at pH 7 were discovered to be exceptionally advantageous to the catalytic rate. In contrast to the few previous studies of TRIS buffer with electrocatalysts (14, 15, 18), we utilized TRIS at a high concentration. At pH 7, TRIS is sufficiently in the cationic protonated form that additional electrolyte such as KCl is not needed for conductance. This important distinction from conventional studies allows TRIS to simultaneously play the roles of pH buffer, proton source, and sole electrolyte. There is precedence in employing buffers in a manner in which they are the sole electrolyte (7, 31–34). Referring to such species simply as a “buffer” or as an “electrolyte” is inadequate in representing the three functions including proton source. For the purposes of this paper we term a species that serves all three functions a protic buffer electrolyte (PBE). In the following discussion, a TRIS PBE solution is one in which [TRIS-H]⁺Cl⁻ is the sole electrolyte and the cation is a proton source, and a sodium phosphate PBE solution is one in which Na⁺[H₂PO₄]⁻ is the sole electrolyte and the anion is a proton source.Open in a separate windowFig. 1.(A) Depiction of the 2e⁻ electrocatalytic HER with POEGMA-g-[2Fe-2S] and/or PDMAEMA-g-[2Fe-2S] metallopolymers using TRIS or sodium phosphate protic buffer electrolytes at pH 7. (B) Image of POEGMA-g-[2Fe-2S] with MW = 14,216 grown in silico. The [2Fe-2S] active site is in the center of the polymer, blue represents the polymer backbone, and the rest are the oligo(ethylene glycol) side chains. See SI Appendix for the details of modeling and a larger image.One of the key unanswered questions for these new catalyst systems is whether the metallopolymer composition (i.e., amine side-chain groups) or the PBEs are more important to afford this outstanding catalytic activity. Herein we study the effects of PBEs by comparing the HER performances of a standard platinum catalyst and a [2Fe-2S] metallopolymer catalyst in TRIS PBE solutions, sodium phosphate PBE solutions, and a KCl electrolyte solution without a PBE. For this study, nonionic water-soluble metallopolymers were used, which were made using oligo(ethylene glycol) side-chain groups on the polymer to avoid the possibility of contributing effects of the protonated amino groups of PDMAEMA-g-[2Fe-2S] referred to earlier. The metallopolymer catalyst used in this work is designated as POEGMA-g-[2Fe-2S] (Fig. 1). We previously reported that this water-soluble metallopolymer was largely inactive for H₂ electrocatalysis at neutral pH in phosphate buffer (22). The current findings suggest that the use of electrolytes composed of inexpensive cationic organic proton donors can be readily applied to any homogeneous or heterogeneous electrocatalyst system as a facile means to enhance HER activity.     

Reliability and validity of the UTBAS-TR (The Unhelpful Thoughts and Beliefs Scale-the Turkish version) in the Turkish population

Abstract

Purpose: This paper decribes the development of the Turkish adaptation of UTBAS (UTBAS-TR) and reports the results concerning its applicability and psychometric structure.

Method: The sample consisted of 81 males and 19 females diagnosed with developmental stuttering in two centres. Test-retest reliability score was obtained by correlating results of repeated aplications of the scale within a one-week interval and a paired t-test was calculated to see the differences in the total and UTBAS I, II and III scores. The internal consistency was assessed using the Cronbach’s alpha. Construct validity was also assessed by examining inter-scale correlations and with the correlations of the UTBAS-TR with two other scales (State-Trait Anxiety Inventory (STAI) and Beck Anxiety Inventory (BAI)).

Result: The internal consistency of the UTBAS-TR and the test and retest reliability score was stati?stically significant. The correlation between UTBAS-TR total score and the UTBAS-TR I, II and III correlations were high. A significant correlation was observed between UTBAS-TR total score with State Anxiety Inventory. However, the correlations between UTBAS-TR-Total Score and Trait Anxiety Inventory and Beck Anxiety Inventory were low.

Conclusion: The UTBAS-TR proved to be suitable for use with the Turkish population.     

Association between periodontitis and medication-related osteonecrosis of the jaw: A systematic review and meta-analysis

Consensus has yet to be reached about the prevention and treatment of medication-related osteonecrosis of the jaw (MRONJ), which is a treatment sequela of several antiresorptive therapies and other pharmaceutical interventions. Several epidemiologic studies have identified periodontal disease (PD) as a risk factor for this outcome. Thus, the objective of this systematic review and meta-analysis was to investigate this association and its magnitude. A systematic search in MEDLINE via PubMed, Scopus and ISI Web of Science, and a meta-analysis were undertaken. Observational studies that gathered information regarding prefixed definitions for both outcomes were selected, and the relevant information was then extracted, and their risk of bias was evaluated using the Newcastle-Ottawa Scale. The protocol of the study was registered on PROSPERO (CRD42019125646). The initial search yielded 757 eligible records, of which 12 were deemed adequate for inclusion (5 cohort studies and 7 case-control studies). On a random-effects meta-analysis, the risk of PD in MRONJ-affected sites compared with at-risk non-affected patients was significantly greater, with a risk ratio of 2.75 (95% CI: 1.67-4.52). Nonetheless, from a pooled analysis of three standardized periodontal measures (ie plaque index, clinical attachment loss and probing depth) no significant results were obtained. MRONJ appears to be associated with an increase in prevalence of PD. The direction of this association, and the factors influencing it must be investigated using further prospective data, and likewise, the possibility for using periodontal therapy as a prevention strategy must be looked into. Periodontal screening needs to be made an indispensable requisite for clinicians in order to establish a correct multidisciplinary approach in MRONJ.