White matter connectivity and social functioning in survivors of pediatric brain tumor.

OBJECTIVE: Survivors of pediatric brain tumors (SPBT) are at risk for social deficits, fewer friendships, and poor peer relations. SPBT also experience reduced brain connectivity via microstructural disruptions to white matter from neurological insults. Research with other populations implicates white matter connectivity as a key contributor to poor social functioning. This case-controlled diffusion-weighted imaging study evaluated structural connectivity in SPBT and typically developing controls (TDC) and associations between metrics of connectivity and social functioning. METHODS: Diffusion weighted-imaging results from 19 SPBT and 19 TDC were analyzed using probabilistic white matter tractography. Survivors were at least 5 years post-diagnosis and 2 years off treatment. Graph theory statistics measured group differences across several connectivity metrics, including average strength, global efficiency, assortativity, clustering coefficient, modularity, and betweenness centrality. Analyses also evaluated the effects of neurological risk on connectivity among SPBT. Correlational analyses evaluated associations between connectivity and indices of social behavior. RESULTS: SPBT demonstrated reduced global connectivity compared to TDC. Several medical factors (e.g., chemotherapy, recurrence, multimodal therapy) were related to decreased connectivity across metrics of integration (e.g., average strength, global efficiency) in SPBT. Connectivity metrics were related to peer relationship quality and social challenges in the SPBT group and to social challenges in the total sample. CONCLUSIONS: Microstructural white matter connectivity is diminished in SPBT and related to neurological risk and peer relationship quality. Additional neuroimaging research is needed to evaluate associations between brain connectivity metrics and social functioning in SPBT.

Social impairment in survivors of pediatric brain tumors via reduced social attention and emotion-specific facial expression recognition.

BACKGROUND/OBJECTIVES: Survivors of pediatric brain tumors (SPBT) experience significant social challenges, including fewer friends and greater isolation than peers. Difficulties in face processing and visual social attention have been implicated in these outcomes. This study evaluated facial expression recognition (FER), social attention, and their associations with social impairments in SPBT. METHODS: SPBT (N = 54; ages 7-16) at least 2 years post treatment completed a measure of FER, while parents completed measures of social impairment. A subset (N = 30) completed a social attention assessment that recorded eye gaze patterns while watching videos depicting pairs of children engaged in joint play. Social Prioritization scores were calculated, with higher scores indicating more face looking. Correlations and regression analyses evaluated associations between variables, while a path analysis modeling tool (PROCESS) evaluated the indirect effects of Social Prioritization on social impairments through emotion-specific FER. RESULTS: Poorer recognition of angry and sad facial expressions was significantly correlated with greater social impairment. Social Prioritization was positively correlated with angry FER but no other emotions. Social Prioritization had significant indirect effects on social impairments through angry FER. CONCLUSION: Findings suggest interventions aimed at improving recognition of specific emotions may mitigate social impairments in SPBT. Further, reduced social attention (i.e., diminished face looking) could be a factor in reduced face processing ability, which may result in social impairments. Longitudinal research is needed to elucidate temporal associations between social attention, face processing, and social impairments.

Creation of a versatile automated two-step purification system with increased throughput capacity for preclinical mAb material generation.

The ever-increasing speed of biotherapeutic drug discovery has driven the development of automated and high throughput purification capabilities. Typically, purification systems require complex flow paths or third-party components that are not found on a standard fast protein liquid chromatography instrument (FPLC) (e.g., Cytiva's ÄKTA) to enable higher throughput. In early mAb discovery there is often a trade-off between throughput and scale where a high-throughput process requires miniaturized workflows necessitating a sacrifice in the amount of material generated. At the interface of discovery and development, flexible automated systems are required that can perform purifications in a high-throughput manner, while also generating sufficient quantities of preclinical material for biophysical, developability, and preclinical animal studies. In this study we highlight the engineering efforts to generate a highly versatile purification system capable of balancing the purification requirements between throughput, chromatographic versatility, and overall product yields. We incorporated a 150 mL Superloop into an ÄKTA FPLC system to expand our existing purification capabilities. This allowed us to perform a range of automated two-step tandem purifications including primary affinity captures (protein A (ProA)/immobilized metal affinity chromatography (IMAC)/antibody fragment (Fab)) followed by secondary polishing with either size exclusion (SEC) or cation exchange (CEX) chromatography. We also integrated a 96 deep-well plate fraction collector into the ÄKTA FPLC system with purified protein fractions being analyzed by a plate based high performance liquid chromatography instrument (HPLC). This streamlined automated purification workflow allowed us to process up to 14 samples within 24 h, enabling purification of ∼1100 proteins, monoclonal antibodies (mAbs), and mAb related protein scaffolds during a 12-month period. We purified a broad range of cell culture supernatant volumes, between 0.1 and 2 L, with final purification yields up to 2 g. The implementation of this new automated, streamlined protein purification process greatly expanded our sample throughput and purification versatility while also enabling the accelerated production of greater quantities of biotherapeutic candidates for preclinical in vivo animal studies and developability assessment.

Reduced Fusiform Gyrus Activation During Face Processing in Pediatric Brain Tumor Survivors.

OBJECTIVE: The neural mechanisms contributing to the social problems of pediatric brain tumor survivors (PBTS) are unknown. Face processing is important to social communication, social behavior, and peer acceptance. Research with other populations with social difficulties, namely autism spectrum disorder, suggests atypical brain activation in areas important for face processing. This case-controlled functional magnetic resonance imaging (fMRI) study compared brain activation during face processing in PBTS and typically developing (TD) youth. METHODS: Participants included 36 age-, gender-, and IQ-matched youth (N = 18 per group). PBTS were at least 5 years from diagnosis and 2 years from the completion of tumor therapy. fMRI data were acquired during a face identity task and a control condition. Groups were compared on activation magnitude within the fusiform gyrus for the faces condition compared to the control condition. Correlational analyses evaluated associations between neuroimaging metrics and indices of social behavior for PBTS participants. RESULTS: Both groups demonstrated face-specific activation within the social brain for the faces condition compared to the control condition. PBTS showed significantly decreased activation for faces in the medial portions of the fusiform gyrus bilaterally compared to TD youth, ps ≤ .004. Higher peak activity in the left fusiform gyrus was associated with better socialization (r = .53, p < .05). CONCLUSIONS: This study offers initial evidence of atypical activation in a key face processing area in PBTS. Such atypical activation may underlie some of the social difficulties of PBTS. Social cognitive neuroscience methodologies may elucidate the neurobiological bases for PBTS social behavior.

Face Processing and Social Functioning in Pediatric Brain Tumor Survivors.

OBJECTIVE: Pediatric brain tumor survivors (PBTS) experience deficits in social functioning. Facial expression and identity recognition are key components of social information processing and are widely studied as an index of social difficulties in youth with autism spectrum disorder (ASD) and other neurodevelopmental conditions. This study evaluated facial expression and identity recognition among PBTS, youth with ASD, and typically developing (TD) youth, and the associations between these face processing skills and social impairments. METHODS: PBTS (N = 54; ages 7-16) who completed treatment at least 2 years prior were matched with TD (N = 43) youth and youth with ASD (N = 55) based on sex and IQ. Parents completed a measure of social impairments and youth completed a measure of facial expression and identity recognition. RESULTS: Groups significantly differed on social impairments (p < .001), with youth with ASD scoring highest followed by PBTS and lastly TD youth. Youth with ASD performed significantly worse on the two measures of facial processing, while TD youth and PBTS were not statistically different. The association of facial expression recognition and social impairments was moderated by group, such that PBTS with higher levels of social impairment performed worse on the expression task compared to TD and ASD groups (p < .01, η2 = 0.07). CONCLUSIONS: Variability in face processing may be uniquely important to the social challenges of PBTS compared to other neurodevelopmental populations. Future directions include prospectively examining associations between facial expression recognition and social difficulties in PBTS and face processing training as an intervention for PBTS.

Diminished social attention in pediatric brain tumor survivors: Using eye tracking technology during naturalistic social perception.

OBJECTIVE: The etiology of pediatric brain tumor survivor (PBTSs) social difficulties is not well understood. A model of social competence for youth with brain disorder and evidence from youth with autism spectrum disorder (ASD) suggests that diminished social attention may underlie social deficits in PBTSs. This study used eye tracking technology to compare visual social attention in PBTSs, youth with ASD, and typically developing (TD) youth. METHODS: Participants included 90 age-, gender-, and IQ-matched youth (N = 30 per group). PBTSs were at least 5 years from diagnosis and 2 years from the completion of tumor-directed therapy. Participants' eye gaze patterns were recorded while watching an established social play paradigm that presented videos of children engaging in either interactive or parallel play. Group differences in proportional gaze duration toward social versus nonsocial areas of interest were compared. Medical correlates of social attention in PBTSs were evaluated. RESULTS: Groups significantly differed in gaze preference across conditions, with PBTSs looking less at social areas of interest than TD youth and in a manner comparable to youth with ASD. Among PBTSs, multimodal tumor-directed therapy was associated with reduced gaze preference for faces. CONCLUSIONS: This study provides the first evidence of disrupted social attention in PBTSs, with parallels to the social attention deficits observed in ASD. Findings offer a new way to conceptualize the social difficulties of PBTSs and could guide interventions aimed at improving PBTS social adjustment by increasing visual attention to socially relevant information during social interactions. (PsycINFO Database Record (c) 2020 APA, all rights reserved).

Involvement of the anterior thalamic radiation in boys with high functioning autism spectrum disorders: a Diffusion Tensor Imaging study.

BACKGROUND: Autism has been hypothesized to reflect neuronal disconnection. Several recent reports implicate the key thalamic relay nuclei and cortico-thalamic connectivity in the pathophysiology of autism. Accordingly, we aimed to focus on evaluating the integrity of the thalamic radiation and sought to replicate prior white matter findings in Korean boys with high-functioning autism spectrum disorders (ASD) using Diffusion Tensor Imaging (DTI). METHODS: We compared fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD) and radial diffusivity (RD) in 17 boys with ASD and 17 typically developing controls in the anterior thalamic radiation (ATR), superior thalamic radiation (STR), posterior thalamic radiation (PTR), corpus callosum (CC), uncinate fasciculus (UF) and inferior longitudinal fasciculus (ILF). RESULTS: The two groups were group-matched on age, IQ, handedness and head circumference. In whole-brain voxel-wise analyses, FA was significantly reduced and MD was significantly increased in the right ATR, CC, and left UF in subjects with ASD (p<0.05, corrected). We found significantly lower FA in right and left ATR, CC, left UF and right and left ILF and significantly higher MD values of the CC in the ASD group in region of interest-based analyses. We also observed significantly higher RD values of right and left ATR, CC, left UF, left ILF in subjects with ASD compared to typically developing boys and significantly lower AD values of both ILF. Right ATR and right UF FA was significantly negatively correlated with total SRS score within the ASD group (r=-.56, p=.02). CONCLUSIONS: Our preliminary findings support evidence implicating disturbances in the thalamo-frontal connections in autism. These findings highlight the role of hypoconnectivity between the frontal cortex and thalamus in ASD.

Tumor lysis syndrome after bortezomib therapy for plasma cell leukemia.

Tumor lysis syndrome (TLS) is a manifestation of metabolic disturbances that can lead to severe treatment complications and ultimately life-threatening events. This syndrome has been reported in solid tumors but is more common in bulky, hyperproliferative malignancies. Tumor lysis syndrome in plasma cell malignancies is less common due to the low turnover rate of the malignant B cells. Bortezomib is the first proteasome inhibitor approved by the United States Food and Drug Administration as second- and third-line therapy for patients with relapsed multiple myeloma. We describe the case of a patient with plasma cell leukemia treated with bortezomib who developed TLS. Bortezomib was begun as single-agent therapy that resulted in the development of TLS after the third dose of the first cycle. Evaluation with the Naranjo Adverse Drug Reaction Probability Scale indicated a probable relationship between TLS and bortezomib in this patient. Patients receiving bortezomib may be at risk for TLS, especially if they have high tumor burden, rapidly proliferative disease, and unfavorable cytogenetics.