Loss of Dnmt3a increases self-renewal and resistance to pegIFN-α in JAK2-V617F-positive myeloproliferative neoplasms.

ABSTRACT: Pegylated interferon alfa (pegIFN-α) can induce molecular remissions in patients with JAK2-V617F-positive myeloproliferative neoplasms (MPNs) by targeting long-term hematopoietic stem cells (LT-HSCs). Additional somatic mutations in genes regulating LT-HSC self-renewal, such as DNMT3A, have been reported to have poorer responses to pegIFN-α. We investigated whether DNMT3A loss leads to alterations in JAK2-V617F LT-HSC functions conferring resistance to pegIFN-α treatment in a mouse model of MPN and in hematopoietic progenitors from patients with MPN. Long-term treatment with pegIFN-α normalized blood parameters and reduced splenomegaly and JAK2-V617F chimerism in single-mutant JAK2-V617F (VF) mice. However, pegIFN-α in VF;Dnmt3aΔ/Δ (VF;DmΔ/Δ) mice worsened splenomegaly and failed to reduce JAK2-V617F chimerism. Furthermore, LT-HSCs from VF;DmΔ/Δ mice compared with VF were less prone to accumulate DNA damage and exit dormancy upon pegIFN-α treatment. RNA sequencing showed that IFN-α induced stronger upregulation of inflammatory pathways in LT-HSCs from VF;DmΔ/Δ than from VF mice, indicating that the resistance of VF;DmΔ/Δ LT-HSC was not due to failure in IFN-α signaling. Transplantations of bone marrow from pegIFN-α-treated VF;DmΔ/Δ mice gave rise to more aggressive disease in secondary and tertiary recipients. Liquid cultures of hematopoietic progenitors from patients with MPN with JAK2-V617F and DNMT3A mutation showed increased percentages of JAK2-V617F-positive colonies upon IFN-α exposure, whereas in patients with JAK2-V617F alone, the percentages of JAK2-V617F-positive colonies decreased or remained unchanged. PegIFN-α combined with 5-azacytidine only partially overcame resistance in VF;DmΔ/Δ mice. However, this combination strongly decreased the JAK2-mutant allele burden in mice carrying VF mutation only, showing potential to inflict substantial damage preferentially to the JAK2-mutant clone.

The Value of Interpersonal Network Continuity for College Students in Disruptive Times.

The COVID-19 pandemic-related social distancing practices that colleges implemented in Spring 2020 disrupted the typical mechanisms of propinquity (physical proximity) and homophily (shared characteristics) that physical institutions rely on to help students build and maintain relationships critical to learning and wellbeing. To explore how social distancing shaped students' academic and social networks and associated educational outcomes, we conceptualized it as a "network shock" and collected unique ego network data in April 2020. For participating students, maintaining interactions with the same set of individuals before and after social distancing was related to more positive outcomes across a range of self-reported wellbeing and learning indicators. On average, students experienced a loss of frequent academic contacts, while they maintained or replaced social interactions in their interpersonal networks after social distancing. Our investigation of the ways students experienced changes in their social and academic networks after a loss of physical proximity points to the role of interpersonal interaction network continuity for fostering wellbeing and learning in times of disruption, as well as the potential need for support in maintaining or rebuilding academic networks.

Pharmacokinetic modelling and simulation to optimize albendazole dosing in hookworm- or Trichuris trichiura-infected infants to adults.

BACKGROUND: Albendazole is the most commonly used drug in preventive chemotherapy programmes against soil-transmitted helminth (STH) infections, with the standard dose of 400 mg resulting in suboptimal clinical outcomes. Population pharmacokinetic (PK) models that could inform dosing strategies are not yet available. METHODS: A population pharmacokinetic model was developed based on micro-blood samples collected from 252 patients aged 2 to 65 years, infected with either hookworm or Trichuris trichiura and treated with albendazole doses ranging from of 200 to 800 mg. An exposure-response analysis was performed relating albendazole and its two metabolites to cure rates and egg reduction rates (ERR). Finally, model-based simulations were conducted to determine equivalent exposure coverage in infants to adults. RESULTS: A population PK model, with one distribution compartment for each compound and one peripheral compartment, following oral administration with a lag time, assuming first-order absorption and linear elimination, best described the concentration-time profiles. Clearance and volume parameters were scaled to body size (weight for albendazole and height for albendazole sulfoxide and sulfone). Dose proportionality was observed for the active metabolite, albendazole sulfoxide, but only in hookworm-infected individuals, with increasing exposure resulting in increased ERR. Exposure of sulfoxide was lowest in the tallest individuals. CONCLUSIONS: Pharmacometric simulations indicate that doses up to 800 mg could further increase albendazole efficacy in hookworm-infected adults, whereas the standard dose of 400 mg is sufficient in the youngest age cohorts. In the absence of evidence-based arguments for adjusting albendazole doses in T. trichiura-infected individuals, the search for new treatment options is further emphasized.

Influence of microsurgical decompression on segmental stability of the lumbar spine - One-year results in a prospective, consecutive case series using upright, kinetic-positional MRI.

BACKGROUND: Standard procedure in patients with lumbar spinal canal stenosis is decompression to relieve the neural structures. Clinical results generally show superiority compared to nonoperative therapy after an observation period of several years. However, there is still a question of postsurgical segmental stability and correlation to clinical findings. Therefore, the aim of this prospective study was to evaluate the clinical outcome in patients who underwent microsurgical decompression in lumbar spine and particularly to analyze intervertebral movement by use of upright, kinetic-positional magnetic resonance imaging (MRI) over a period of 12 months and then to correlate the clinical and imaging data with each other. METHODS: Complete clinical data of 24 consecutive participants with microsurgical decompression of the lumbar spine were obtained by questionnaires including visual analogue scale (VAS) for back and leg, Oswestry Disability Index (ODI), Roland-Morris Disability Questionnaire (RMDQ), Short-Form-36 (SF-36), walking distance and use of analgesics with assessment preoperatively and after 6 weeks and 12 months. At the same points of time all patients underwent upright, kinetic-positional MRI to measure intersegmental motion of the operated levels with determination of intervertebral angles and translation and to correlate the clinical and imaging data with each other. RESULTS: VAS for leg, ODI, RMDQ and physical component scale of SF-36 improved statistically significantly without statistically significant differences regarding intersegmental motion and horizontal displacement 6 weeks and 12 months after operation. Regression analysis did not find any linear dependencies between the clinical scores and imaging parameters. CONCLUSIONS: In awareness of some limitations of the study, our results demonstrate no increase of intersegmental movement or even instability after microsurgical decompression of the lumbar spine over a follow-up period of 12 months, which is equivalent to preservation of intervertebral stability. Furthermore, the magnitude of intervertebral range of motion showed no correlation to the clinical score parameters at all three examination points of time.

Pharmacometric Analysis of Tribendimidine Monotherapy and Combination Therapies To Achieve High Cure Rates in Patients with Hookworm Infections.

In the treatment of hookworm infections, pharmacotherapy has been only moderately successful and drug resistance is a threat. Therefore, novel treatment options including combination therapies should be considered, in which tribendimidine could play a role. Our aims were to (i) characterize the pharmacokinetics of tribendimidine's metabolites in adolescents receiving tribendimidine monotherapy or in combination with ivermectin or oxantel pamoate, (ii) evaluate possible drug-drug interactions (DDI), (iii) link exposure to response, and (iv) identify a treatment strategy associated with high efficacy, i.e., >90% cure rates (CRs), utilizing model-based simulations. A population pharmacokinetic model was developed for tribendimidine's primary and secondary metabolites, dADT and adADT, in 54 hookworm-positive adolescents, with combination therapy evaluated as a possible covariate. Subsequently, an exposure-response analysis was performed utilizing CRs as response markers. Simulations were performed to identify a treatment strategy to achieve >90% CRs. A two-compartmental model best described metabolite disposition. No pharmacokinetic DDI was identified with ivermectin or oxantel pamoate. All participants receiving tribendimidine plus ivermectin were cured. For the monotherapy arm and the arm including the combination with oxantel pamoate, Emax models adequately described the correlation between dADT exposure and probability of being cured, with required exposures to achieve 50% of maximum effect of 39.6 and 15.6 nmol/ml·h, respectively. Based on our simulations, an unrealistically high monotherapy tribendimidine dose would be necessary to achieve CRs of >90%, while combination therapy with ivermectin would meet this desired target product profile. Further clinical studies should be launched to develop this combination for the treatment of hookworm and other helminth infections.

Meta-analyses identify differentially expressed micrornas in Parkinson's disease.

OBJECTIVE: MicroRNA (miRNA)-mediated (dys)regulation of gene expression has been implicated in Parkinson's disease (PD), although results of miRNA expression studies remain inconclusive. We aimed to identify miRNAs that show consistent differential expression across all published expression studies in PD. METHODS: We performed a systematic literature search on miRNA expression studies in PD and extracted data from eligible publications. After stratification for brain, blood, and cerebrospinal fluid (CSF)-derived specimen, we performed meta-analyses across miRNAs assessed in three or more independent data sets. Meta-analyses were performed using effect-size- and p-value-based methods, as applicable. RESULTS: After screening 599 publications, we identified 47 data sets eligible for meta-analysis. On these, we performed 160 meta-analyses on miRNAs quantified in brain (n = 125), blood (n = 31), or CSF (n = 4). Twenty-one meta-analyses were performed using effect sizes. We identified 13 significantly (Bonferroni-adjusted α = 3.13 × 10-4 ) differentially expressed miRNAs in brain (n = 3) and blood (n = 10) with consistent effect directions across studies. The most compelling findings were with hsa-miR-132-3p (p = 6.37 × 10-5 ), hsa-miR-497-5p (p = 1.35 × 10-4 ), and hsa-miR-133b (p = 1.90 × 10-4 ) in brain and with hsa-miR-221-3p (p = 4.49 × 10-35 ), hsa-miR-214-3p (p = 2.00 × 10-34 ), and hsa-miR-29c-3p (p = 3.00 × 10-12 ) in blood. No significant signals were found in CSF. Analyses of genome-wide association study data for target genes of brain miRNAs showed significant association (α = 9.40 × 10-5 ) of genetic variants in nine loci. INTERPRETATION: We identified several miRNAs that showed highly significant differential expression in PD. Future studies may assess the possible role of the identified brain miRNAs in pathogenesis and disease progression as well as the potential of the top blood miRNAs as biomarkers for diagnosis, progression, or prediction of PD. ANN NEUROL 2019;85:835-851.

In Vitro and In Vivo Drug-Drug Interaction Study of the Effects of Ivermectin and Oxantel Pamoate on Tribendimidine.

Soil-transmitted helminth (STH) infections still remain a major health problem in poor rural settings. The lack of efficacious drugs against all STH species raises interest in drug combinations. Drug-drug interactions (DDIs) are, however, of major concern, so careful in vitro and in vivo characterization is needed. The combination of tribendimidine with either ivermectin or oxantel pamoate targets a broad range of STHs and thus represents a promising treatment alternative. Drug-drug interactions, however, have not yet been investigated. Therefore, the effects of combinations of ivermectin, oxantel pamoate, and tribendimidine's active metabolite deacylated amidantel (dADT) on cytochrome P450 (CYP450) metabolism were evaluated, followed by a pharmacokinetic analysis of tribendimidine and ivermectin alone and in combination in healthy rats. Oxantel pamoate is only poorly absorbed and was therefore excluded from pharmacokinetic analysis. No evident effect was observed for tribendimidine-oxantel pamoate at the CYP450 metabolism level, whereas a combination of tribendimidine and ivermectin led to moderately increased CYP2D6 inhibition compared to ivermectin or tribendimidine alone. Coadministration of tribendimidine with ivermectin altered neither the time to maximum concentration of drug in plasma (Tmax) nor the elimination half-lives of dADT, the acetylated derivative of amidantel (adADT), and ivermectin. While the area under the concentration-versus-time curve (AUC) and maximum concentration of drug in plasma (Cmax) values of dADT, adADT, and ivermectin are reduced by coadministration, the change is insufficient to declare that a DDI has been detected. Further studies are necessary to understand the observed interaction of tribendimidine and ivermectin, which is not related to P450 metabolism, and its significance for the situation in humans.

Pharmacokinetics of Albendazole, Albendazole Sulfoxide, and Albendazole Sulfone Determined from Plasma, Blood, Dried-Blood Spots, and Mitra Samples of Hookworm-Infected Adolescents.

Albendazole is an effective anthelmintic intensively used for decades. However, profound pharmacokinetic (PK) characterization is missing in children, the population mostly affected by helminth infections. Blood microsampling would facilitate PK studies in pediatric populations but has not been applied to quantify albendazole's disposition. Quantification methods were developed and validated using liquid chromatography-tandem mass spectrometry to analyze albendazole and its metabolites albendazole sulfoxide and albendazole sulfone in wet samples (plasma and blood) and blood microsamples (dried-blood spots [DBS]; Mitra). The use of DBS was limited by a matrix effect and poor recovery, but the extraction efficiency was constant throughout the concentration range. Hookworm-infected adolescents were venous and capillary blood sampled posttreatment with 400 mg albendazole and 25 mg/kg oxantel pamoate. Similar half-life (t1/2 = ∼1.5 h), time to reach the maximum concentration (tmax = ∼2 h), and maximum concentration (Cmax = 12.5 to 26.5 ng/ml) of albendazole were observed in the four matrices. The metabolites reached Cmax after ∼4 h with a t1/2 of ca. 7 to 8 h. A statistically significant difference in albendazole sulfone's t1/2 as determined by using DBS and wet samples was detected. Cmax of albendazole sulfoxide (288 to 380 ng/ml) did not differ among the matrices, but higher Cmax of albendazole sulfone were obtained in the two microsampling devices (22 ng/ml) versus the wet matrices (14 ng/ml). In conclusion, time-concentration profiles and PK results of the four matrices were similar, and the direct comparison of the two microsampling devices indicates that Mitra extraction was more robust during validation and can be recommended for future albendazole PK studies.

Pharmacokinetics of ascending doses of ivermectin in Trichuris trichiura-infected children aged 2-12 years.

BACKGROUND: Yearly, millions of children are treated globally with ivermectin mainly for neglected tropical diseases. Anatomical, physiological and biochemical differences between children and adults may result in changes in pharmacokinetics. However, paediatric pharmacokinetic data of ivermectin are lacking. METHODS: In the framework of a randomized controlled dose-finding trial in rural Côte d'Ivoire, Trichuris trichiura-infected pre-school-aged children (PSAC, 2-5 years) and school-aged children (SAC, 6-12 years) were assigned to 100 or 200 µg/kg and 200, 400 or 600 µg/kg ivermectin, respectively (ISRCTN registry no. ISRCTN15871729). Capillary blood was collected on dried blood spot cards until 72 h post-treatment. Ivermectin was quantified by LC-MS/MS, and pharmacokinetic parameters were evaluated by non-compartmental analysis. RESULTS: C max and AUC increased in PSAC and SAC with ascending doses and were similar in both age groups when the current standard dose (200 µg/kg) was administered (∼23 ng/mL and ∼350 ng×h/mL, respectively). PSAC with lower BMI were associated with significantly higher AUCs. AUC and Cmax were ∼2-fold lower in children compared with parameters previously studied in adults, whereas body weight-adjusted CL/F (∼0.35 L/h/kg) was significantly higher in children. Tmax (∼6 h), t1/2 (∼18 h), mean residence time (MRTINF) (∼28 h) and V/F (∼8 L/kg) were similar in all paediatric treatment arms. CONCLUSIONS: A positive association of AUC or Cmax with dose was observed in both age groups. Undernutrition might influence the AUC of ivermectin in PSAC. Ivermectin shows a lower exposure profile in children compared with adults, highlighting the need to establish dosing recommendations for different age groups.

Differential expression of microRNAs in Alzheimer's disease brain, blood, and cerebrospinal fluid.

INTRODUCTION: Several microRNAs (miRNAs) have been implicated in Alzheimer's disease pathogenesis, but the evidence from individual case-control studies remains inconclusive. METHODS: A systematic literature review was performed, followed by standardized multistage data extraction, quality control, and meta-analyses on eligible data for brain, blood, and cerebrospinal fluid specimens. Results were compared with miRNAs reported in the abstracts of eligible studies or recent qualitative reviews to assess novelty. RESULTS: Data from 147 independent data sets across 107 publications were quantitatively assessed in 461 meta-analyses. Twenty-five, five, and 32 miRNAs showed studywide significant differential expression (α < 1·08 × 10-4) in brain, cerebrospinal fluid, and blood-derived specimens, respectively, with 5 miRNAs showing differential expression in both brain and blood. Of these 57 miRNAs, 13 had not been reported in the abstracts of previous original or review articles. DISCUSSION: Our systematic assessment of differential miRNA expression is the first of its kind in Alzheimer's disease and highlights several miRNAs of potential relevance.

Efficacy and Safety of Ivermectin Against Trichuris trichiura in Preschool-aged and School-aged Children: A Randomized Controlled Dose-finding Trial.

Background: Although trichuriasis affects millions of children worldwide, recommended drugs lack efficacy and new treatment options are urgently needed. Ivermectin has promising potential to complement the anthelminthic armamentarium. Methods: A randomized placebo-controlled trial was conducted in rural Côte d'Ivoire to provide evidence on the efficacy and safety of ascending oral ivermectin dosages in preschool-aged children (PSAC) and school-aged children (SAC) infected with Trichuris trichiura. The primary outcome was the cure rate (CR) for T. trichiura infection, and the secondary outcomes were safety, egg-reduction rates (ERRs) against T. trichiura infection, and CRs and ERRs against other soil-transmitted helminth species. Results: A total of 126 PSAC and 166 SAC were included in an available case analysis. In PSAC, efficacy against T. trichiura did not differ between 200 µg/kg ivermectin and placebo treatment arm, as expressed in CRs (20.9% [95% confidence interval {CI}, 11.9%-52.8%] vs 19.5% [10.4%-49.9%]) and geometric mean ERRs (78.6% [60.1%-89.5%] vs 68.2% [40.5%-84.8%]). In SAC, the highest administered ivermectin dose of 600 µg/kg had a low CRs (12.2% [95% CI, 4.8%-32.3%]) and moderate ERRs (66.3% [43.8%-80.2%]). Only mild adverse events and no organ toxicity, based on serum biomarkers, was observed. Conclusion: Ivermectin can be administered safely to PSAC with trichuriasis. Given the low efficacy of ivermectin monotherapy against T. trichiura infection, further research should investigate the optimal drug combinations and dosages with ivermectin against soil-transmitted helminthiasis. Clinical Trials Registration: ISRCTN15871729 (www.isrctn.com).

Impact of scaffold rigidity on the design and evolution of an artificial Diels-Alderase.

By combining targeted mutagenesis, computational refinement, and directed evolution, a modestly active, computationally designed Diels-Alderase was converted into the most proficient biocatalyst for [4+2] cycloadditions known. The high stereoselectivity and minimal product inhibition of the evolved enzyme enabled preparative scale synthesis of a single product diastereomer. X-ray crystallography of the enzyme-product complex shows that the molecular changes introduced over the course of optimization, including addition of a lid structure, gradually reshaped the pocket for more effective substrate preorganization and transition state stabilization. The good overall agreement between the experimental structure and the original design model with respect to the orientations of both the bound product and the catalytic side chains contrasts with other computationally designed enzymes. Because design accuracy appears to correlate with scaffold rigidity, improved control over backbone conformation will likely be the key to future efforts to design more efficient enzymes for diverse chemical reactions.

Transparent thin shield for radio frequency transmit coils.

OBJECTIVE: To identify a shielding material compatible with optical head-motion tracking for prospective motion correction and which minimizes radio frequency (RF) radiation losses at 7 T without sacrificing line-of-sight to an imaging target. MATERIALS AND METHODS: We evaluated a polyamide mesh coated with silver. The thickness of the coating was approximated from the composition ratio provided by the material vendor and validated by an estimate derived from electrical conductivity and light transmission measurements. The performance of the shield is compared to a split-copper shield in the context of a four-channel transmit-only loop array. RESULTS: The mesh contains less than a skin-depth of silver coating (300 MHz) and attenuates light by 15 %. Elements of the array vary less in the presence of the mesh shield as compared to the split-copper shield indicating that the array behaves more symmetrically with the mesh shield. No degradation of transmit efficiency was observed for the mesh as compared to the split-copper shield. CONCLUSION: We present a shield compatible with future integration of camera-based motion-tracking systems. Based on transmit performance and eddy-current evaluations the mesh shield is appropriate for use at 7 T.

Parental problem drinking and adolescent externalizing behaviors: The mediating role of family functioning.

This study explored relationships among parental problem drinking, family functioning, and adolescent externalizing behaviors. The unique effects of maternal and paternal drinking were examined separately for girls and boys. The sample included 14-19 year old U.S. adolescents (Mage = 16.15; SD = .75; 52.5% female) and their parents. Participants completed surveys in the spring of 2007 and 2008. Structural equation modeling was used to conduct path analysis models. Results showed the distinctive and adverse effects of parental problem drinking on adolescent alcohol use, drug use, rule breaking, and aggressive behavior over time. Findings also highlighted the indirect and mediating roles of family functioning. For both girls and boys, family cohesion mediated the relationship between parental problem drinking and adolescent externalizing behaviors. For girls, adolescent-father communication predicted increased externalizing behaviors over time. These findings draw attention to the importance of exploring adolescent and parent gender when examining parental problem drinking, family functioning, and externalizing behaviors.

A Long-Term Longitudinal Examination of the Effect of Early Onset of Alcohol and Drug Use on Later Alcohol Abuse.

BACKGROUND: Early onset of alcohol use has been linked to later alcohol problems in adulthood. Currently, it is not clear whether early onset of marijuana and tobacco use similarly predicts alcohol problems. Moreover, most studies examining the effect of early substance use onset on later problems only have followed youth into their early 20s. Therefore, the primary goal of this study was to examine whether early onset of alcohol, marijuana, and tobacco use predicts alcohol problems beyond the transition to adulthood. METHODS: The sample included 225 15-19-year-old youth (60% girls; 62% Caucasian) who were surveyed in three time periods: 1993-1998 (Time 1), 1998-2003 (Time 2), and 2003-2007 (Time 3). Participants reported their age of onset for regular drinking, tobacco use, and marijuana use. At each time of measurement, they also completed surveys relating to their alcohol use and abuse. RESULTS: Participants with an earlier age of onset of drinking regularly scored higher on the Michigan Alcoholism Screening Test (MAST) and drank more frequently to get high and drunk throughout their 20s. Tobacco use onset and marijuana use onset were not associated with later alcohol use or abuse. CONCLUSIONS: Results from this study suggest that the relationship between the onset of substance use and later substance abuse may be substance specific. Of note, early onset of regular drinking was associated with alcohol problems during adulthood, underscoring the importance of delaying the onset of regular alcohol use among youth.

Novel role of the serine protease inhibitor elafin in gluten-related disorders.

OBJECTIVES: Elafin, an endogenous serine protease inhibitor, modulates colonic inflammation. We investigated the role of elafin in celiac disease (CD) using human small intestinal tissues and in vitro assays of gliadin deamidation. We also investigated the potential beneficial effects of elafin in a mouse model of gluten sensitivity. METHODS: Epithelial elafin expression in the small intestine of patients with active CD, treated CD, and controls without CD was determined by immunofluorescence. Interaction of elafin with human tissue transglutaminase-2 (TG-2) was investigated in vitro. The 33-mer peptide, a highly immunogenic gliadin peptide, was incubated with TG-2 and elafin at different concentrations. The degree of deamidation of the 33-mer peptide was analyzed by liquid chromatography-mass spectrometry. Elafin was delivered to the intestine of gluten-sensitive mice using a recombinant Lactococcus lactis vector. Small intestinal barrier function, inflammation, proteolytic activity, and zonula occludens-1 (ZO-1) expression were assessed. RESULTS: Elafin expression in the small intestinal epithelium was lower in patients with active CD compared with control patients. In vitro, elafin significantly slowed the kinetics of the deamidation of the 33-mer peptide to its more immunogenic form. Treatment of gluten-sensitive mice with elafin delivered by the L. lactis vector normalized inflammation, improved permeability, and maintained ZO-1 expression. CONCLUSIONS: The decreased elafin expression in the small intestine of patients with active CD, the reduction of 33-mer peptide deamidation by elafin, coupled to the barrier enhancing and anti-inflammatory effects observed in gluten-sensitive mice, suggest that this molecule may have pathophysiological and therapeutic importance in gluten-related disorders.

Deformable 3D/3D CT-to-digital-tomosynthesis image registration in image-guided bronchoscopy interventions.

Traditional navigational bronchoscopy procedures rely on preprocedural computed tomography (CT) and intraoperative chest radiography and cone-beam CT (CBCT) to biopsy peripheral lung lesions. This navigational approach is challenging due to the projective nature of radiography, and the high radiation dose, long imaging time, and large footprints of CBCT. Digital tomosynthesis (DTS) is considered an attractive alternative combining the advantages of radiography and CBCT. Only the depth resolution cannot match a full CBCT image due to the limited angle acquisition. To address this issue, preoperative CT is a good auxiliary in guiding bronchoscopy interventions. Nevertheless, CT-to-body divergence caused by anatomic changes and respiratory motion, hinders the effective use of CT imaging. To mitigate CT-to-body divergence, we propose a novel deformable 3D/3D CT-to-DTS registration algorithm employing a multistage, multiresolution approach and using affine and elastic B-spline transformation models with bone and lung mask images. A multiresolution strategy with a Gaussian image pyramid and a multigrid strategy within the B-spline model are applied. The normalized correlation coefficient is included in the cost function for the affine model and a multimetric weighted cost function is used for the B-spline model, with weights determined heuristically. Tested on simulated and real patient bronchoscopy data, the algorithm yields promising results. Assessed qualitatively by visual inspection and quantitatively by computing the Dice coefficient (DC) and the average symmetric surface distance (ASSD), the algorithm achieves mean DC of 0.82±0.05 and 0.74±0.05, and mean ASSD of 0.65±0.29mm and 0.93±0.43mm for simulated and real data, respectively. This algorithm lays the groundwork for CT-aided intraoperative DTS imaging in image-guided bronchoscopy interventions with future studies focusing on automated metric weight setting.

Center-out echo-planar spectroscopic imaging with correction of gradient-echo phase and time shifts.

A procedure to prevent the formation of image and spectral Nyquist ghosts in echo-planar spectroscopic imaging is introduced. It is based on a novel Cartesian center-out echo-planar spectroscopic imaging trajectory, referred to as EPSICO, and combined with a correction of the gradient-echo phase and time shifts. Processing of homogenous sets of forward and reflected echoes is no longer necessary, resulting in an optimized spectral width. The proposed center-out trajectory passively prevents the formation of Nyquist ghosts by privileging the acquisition of the center k-space line with forward echoes at the beginning of an echo-planar spectroscopic imaging dwell time and by ensuring that all k-space lines and their respective complex conjugates are acquired at equal time intervals. With the proposed procedure, concentrations of N-acetyl aspartate, creatine, choline, glutamate, and myo-inositol were reliably determined in human white matter at 3 T.

Protein folding at the membrane interface, the structure of Nogo-66 requires interactions with a phosphocholine surface.

Repair of damage to the central nervous system (CNS) is inhibited by the presence of myelin proteins that prevent axonal regrowth. Consequently, growth inhibitors and their common receptor have been identified as targets in the treatment of injury to the CNS. Here we describe the structure of the extracellular domain of the neurite outgrowth inhibitor (Nogo) in a membrane-like environment. Isoforms of Nogo are expressed with a common C terminus containing two transmembrane (TM) helices. The ectodomain between the two TM helices, Nogo-66, is active in preventing axonal growth [GrandPre T, Nakamura F, Vartanian T, Strittmatter SM (2000) Nature 403:439-444]. We studied the structure of Nogo-66 alone and in the presence of 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) vesicles and dodecylphosphocholine (DPC) micelles as membrane mimetics. We find that Nogo-66 is largely disordered when free in solution. However, when bound to a phosphocholine surface Nogo-66 adopts a unique, stable fold, even in the absence of TM anchors. Using paramagnetic probes and protein-DPC nuclear Overhauser effects (NOEs), we define portions of the growth inhibitor likely to be accessible on the cell surface. With these data we predict that residues (28-58) are available to bind the Nogo receptor, which is entirely consistent with functional assays. Moreover, the conformations and relative positions of side chains recognized by the receptor are now defined and provide a foundation for antagonist design.