COVID-19 infection in children, adolescents, and young adults with Down syndrome and hematologic malignancies.

INTRODUCTION: Children, adolescents, and young adults (CAYAs) with Down syndrome (DS) and hematologic malignancies are particularly vulnerable to infections and related complications. There are limited data regarding COVID-19 infections in this group. We aimed to understand the clinical course of COVID-19 in this population. METHODS: This observational study leverages the de-identified clinical and sociodemographic data captured by the Pediatric Oncology COVID-19 Case Report Registry (POCC) regarding CAYAs with cancer and COVID-19. We evaluated CAYAs (≤21 years at COVID-19 infection) with hematologic malignancies and COVID-19 reported from April 1, 2020 to May 2, 2023, comparing those with and without DS. Using multivariable logistic regression, we examined rates of hospitalization, intensive care unit (ICU) admission, respiratory support, and changes in cancer-directed therapy. RESULTS: Among 1408 CAYAs with hematologic malignancies, 55 had DS (CAYA-DS). CAYA-DS had higher rates of hospitalization, ICU admission, and respiratory support (p < .001) than CAYAs without DS. Similarly, multivariable analyses found higher odds of hospitalization (odds ratio [OR] = 2.8, 95% confidence interval [CI]: 1.5-5.1), ICU admission (OR = 4.2, 95% CI: 1.9-9.1), and need for respiratory support (OR = 4.2, 95% CI: 2.0-8.8) among CAYA-DS. Modifications to cancer-directed therapy were more common among CAYA-DS when related to neutropenia (p = .001), but not when unrelated to neutropenia (p = .88); CAYA-DS did not have higher odds of changes to cancer-directed therapy (OR = 1.20, 95% CI: 0.7-2.1). CONCLUSIONS: We identify CAYA-DS with hematologic malignancies as a vulnerable subpopulation at greater risk for severe COVID-19 infection. This can inform conversations with patients and families regarding therapeutic and preventive measures, as well as the risks and benefits of modifying chemotherapy in the setting of COVID-19.

Enhanced long-term memory and increased mushroom body plasticity in Heliconius butterflies.

Heliconius butterflies exhibit expanded mushroom bodies, a key brain region for learning and memory in insects, and a novel foraging strategy unique among Lepidoptera - traplining for pollen. We tested visual long-term memory across six Heliconius and outgroup Heliconiini species. Heliconius species exhibited greater fidelity to learned colors after eight days without reinforcement, with further evidence of recall at 13 days. We also measured the plastic response of the mushroom body calyces over this time period, finding substantial post-eclosion expansion and synaptic pruning in the calyx of Heliconius erato, but not in the outgroup Heliconiini Dryas iulia. In Heliconius erato, visual associative learning experience specifically was associated with a greater retention of synapses and recall accuracy was positively correlated with synapse number. These results suggest that increases in the size of specific brain regions and changes in their plastic response to experience may coevolve to support novel behaviors.

Guidelines for immunological analyses following focused ultrasound treatment.

Focused ultrasound (FUS) is a powerful emerging tool for non-invasive, non-ionizing targeted destruction of tumors. The last two decades have seen a growing body of preclinical and clinical literature supporting the capacity of FUS to increase nascent immune responses to tumors and to potentiate cancer immunotherapies (e.g. checkpoint inhibitors) through a variety of means, including immune modulation and drug delivery. With the rapid acceleration of this field and a multitude of FUS immunotherapy clinical trials having now been deployed worldwide, there is a need to streamline and standardize the methodology for immunological analyses field-wide. Recently, the Focused Ultrasound Foundation and Cancer Research Institute partnered to convene a group of over 85 leaders to discuss the nexus of FUS and immuno-oncology. The guidelines documented herein were assembled in response to recommendations that emerged from this discussion, emphasizing the urgent need for heightened accessibility of immune analysis methods and standardized protocols unique to the field. These guidelines are designated for existing stakeholders in the FUS immuno-oncology domain or those newly entering the field, to provide guidance on collection, storage, and immunological profiling of tissue or blood specimens in the context of FUS immunotherapy studies, and additionally offer templates for standardized deployment of these methods based on collective experience gained within the field to date. These guidelines are tumor-agnostic and provide evidence-based, consensus-based recommendations for both preclinical and clinical immune analysis of tissue and blood specimens.

Cortex cis-regulatory switches establish scale colour identity and pattern diversity in Heliconius.

In Heliconius butterflies, wing colour pattern diversity and scale types are controlled by a few genes of large effect that regulate colour pattern switches between morphs and species across a large mimetic radiation. One of these genes, cortex, has been repeatedly associated with colour pattern evolution in butterflies. Here we carried out CRISPR knockouts in multiple Heliconius species and show that cortex is a major determinant of scale cell identity. Chromatin accessibility profiling and introgression scans identified cis-regulatory regions associated with discrete phenotypic switches. CRISPR perturbation of these regions in black hindwing genotypes recreated a yellow bar, revealing their spatially limited activity. In the H. melpomene/timareta lineage, the candidate CRE from yellow-barred phenotype morphs is interrupted by a transposable element, suggesting that cis-regulatory structural variation underlies these mimetic adaptations. Our work shows that cortex functionally controls scale colour fate and that its cis-regulatory regions control a phenotypic switch in a modular and pattern-specific fashion.

Heliconius butterflies have bright patterns on their wings that tell potential predators that they are toxic. As a result, predators learn to avoid eating them. Over time, unrelated species of butterflies have evolved similar patterns to avoid predation through a process known as Müllerian mimicry. Worldwide, there are over 180,000 species of butterflies and moths, most of which have different wing patterns. How do genes create this pattern diversity? And do butterflies use similar genes to create similar wing patterns? One of the genes involved in creating wing patterns is called cortex. This gene has a large region of DNA around it that does not code for proteins, but instead, controls whether cortex is on or off in different parts of the wing. Changes in this non-coding region can act like switches, turning regions of the wing into different colours and creating complex patterns, but it is unclear how these switches have evolved. Butterfly wings get their colour from tiny structures called scales, which each have their own unique set of pigments. In Heliconius butterflies, there are three types of scales: yellow/white scales, black scales, and red/orange/brown scales. Livraghi et al. used a DNA editing technique called CRISPR to find out whether the cortex gene affects scale type. First, Livraghi et al. confirmed that deleting cortex turned black and red scales yellow. Next, they used the same technique to manipulate the non-coding DNA around the cortex gene to see the effect on the wing pattern. This manipulation turned a black-winged butterfly into a butterfly with a yellow wing band, a pattern that occurs naturally in Heliconius butterflies. The next step was to find the mutation responsible for the appearance of yellow wing bands in nature. It turns out that a bit of extra genetic code, derived from so-called 'jumping genes', had inserted itself into the non-coding DNA around the cortex gene, 'flipping' the switch and leading to the appearance of the yellow scales. Genetic information contains the instructions to generate shape and form in most organisms. These instructions evolve over millions of years, creating everything from bacteria to blue whales. Butterfly wings are visual evidence of evolution, but the way their genes create new patterns isn't specific to butterflies. Understanding wing patterns can help researchers to learn how genetic switches control diversity across other species too.

Recent cocaine use and memory impairment in HIV.

Both Human Immunodeficiency Virus (HIV) and cocaine use have been associated with impairment in neuropsychological functioning. The high comorbidity between HIV and cocaine use highlights the importance of ascertaining whether there is a compounding effect of cocaine use in individuals with HIV. Among neuropsychological domains impacted by HIV, verbal memory deficits have received substantial attention partly because they have been associated with declines in functional status in HIV positive individuals. We collected California Verbal Learning Test-II data from HIV participants who met lifetime diagnostic criteria of cocaine abuse and/or dependence (HIV/CocDx+, N = 80 & HIV/CocDx-, N = 30, respectively) and those with and without recent cocaine use, which was confirmed by toxicology analysis (HIV/Coc+, N = 56 & HIV/Coc-, N = 57, respectively). The Item Specific Deficit Approach (ISDA) was employed to determine any additional cocaine-associated deficits in encoding, consolidation, and retrieval, which attempts to control for potential confounding factors of memory such as attention. Using conventional methods of evaluating memory profiles, we found that the HIV/Coc + group demonstrated worse learning, immediate and delayed free recall, and recognition in contrast to the HIV/Coc - group; although using the ISDA, we found that encoding was the only significant difference between HIV/Coc + and HIV/Coc-participant, with HIV/Coc - performing better. Our data suggest that for individuals with HIV, cocaine use is associated with a temporary decline in verbal memory, is characterized by greater encoding deficits, and these effects may reduce with abstinence. Clinically, our findings suggest that reduced encoding is the likely contributor to verbal memory decline in HIV/Coc + and these effects are partially reversible-at least to the level of their HIV/Coc - counterparts.

Depressive Symptom Profiles Predict Specific Neurodegenerative Disease Syndromes in Early Stages.

Background: During early stages, patients with neurodegenerative diseases (NDG) often present with depressive symptoms. However, because depression is a heterogeneous disorder, more precise delineation of the specific depressive symptom profiles that arise early in distinct NDG syndromes is necessary to enhance patient diagnosis and care. Methods and Findings: Five-hundred and sixty four participants self-reported their depressive symptoms using the Geriatric Depression Scale (GDS), including 111 healthy older control subjects (NC) and 453 patients diagnosed with one of six NDGs who were at the mild stage of disease (CDR® Dementia Staging Instrument ≤ 1) [186 Alzheimer's disease (AD), 76 behavioral variant frontotemporal dementia (bvFTD), 52 semantic variant primary progressive aphasia (svPPA), 46 non-fluent variant PPA (nfvPPA), 49 progressive supranuclear palsy syndrome (PSPS), 44 corticobasal syndrome (CBS)]. The GDS was divided into subscales based on a previously published factor analysis, representing five symptoms (dysphoria, hopelessness, withdrawal, worry, and cognitive concerns). Mixed models were created to examine differences in depression subscale by group, and logistic regression analyses were performed to determine if patterns of depressive symptoms could predict a patient's NDG syndrome. PSPS patients presented with a hopeless, dysphoric, and withdrawn pattern, while patients with CBS presented with a similar but less severe pattern. Worry was a key symptom in the profile of patients with svPPA, while ADs only had abnormally elevated cognitive concerns. Depressive profile accurately predicted NDG diagnosis at a rate of between 70 and 84% accuracy. Conclusions: These results suggest that attention to specific depressive symptom profile can improve diagnostic sensitivity and can be used to provide more individualized patient care.

A subset analysis of a phase II trial evaluating the use of DFMO as maintenance therapy for high-risk neuroblastoma.

Neuroblastoma is a sympathetic nervous system tumor, primarily presenting in children under 6 years of age. The long-term prognosis for patients with high-risk neuroblastoma (HRNB) remains poor despite aggressive multimodal therapy. This report provides an update to a phase II trial evaluating DFMO as maintenance therapy in HRNB. Event-free survival (EFS) and overall survival (OS) of 81 subjects with HRNB treated with standard COG induction, consolidation and immunotherapy followed by 2 years of DFMO on the NMTRC003/003b Phase II trial were compared to a historical cohort of 76 HRNB patients treated at Beat Childhood Cancer Research Consortium (BCC) hospitals who were disease-free after completion of standard upfront therapy and did not receive DFMO. The 2- and 5-year EFS were 86.4% [95% confidence interval (CI) 79.3%-94.2%] and 85.2% [77.8%-93.3%] for the NMTRC003/003b subset vs 78.3% [69.5%-88.3%] and 65.6% [55.5%-77.5%] for the historical control group. The 2- and 5-year OS were 98.8% [96.4-100%] and 95.1% [90.5%-99.9%] vs 94.4% [89.3%-99.9%] and 81.6% [73.0%-91.2%], respectively. DFMO maintenance for HRNB after completion of standard of care therapy was associated with improved EFS and OS relative to historical controls treated at the same institutions. These results support additional investigations into the potential role of DFMO in preventing relapse in HRNB.

Strategy use and verbal memory in older adults: The role of intellectual functioning and the preferential impact of semantic clustering.

Objective: The relative importance of various mechanisms supporting declarative verbal memory among older adults remains uncertain. The present study examined the impact of strategy use (specifically semantic clustering) versus other variables known to impact memory performance (age, sex, education, FSIQ, processing speed, and executive functioning) on verbal memory functioning among healthy older adults.Methods: Healthy older adults from the California Verbal Learning Test, Second Edition standardization sample were selected (N = 242). Relationships between verbal memory, demographics variables, and neuropsychological factors were established, and a hierarchical regression analysis was conducted to examine the individual contributions of these variables in predicting memory performance.Results: Bivariate correlations suggested that memory was significantly related to demographic factors, IQ, executive functioning, and semantic clustering. Importantly, hierarchical regression analysis revealed that semantic clustering significantly and independently contributed to recall performance beyond the demonstrated impacts of FSIQ, speed, executive functioning, and demographic variables. Furthermore, FSIQ did not moderate the relationship between semantic clustering and memory indicating that this strategy is an important factor in bolstering recall, independent of FSIQ.Conclusions: Our results highlight the critical importance of semantic clustering utilization in enhancing memory performance among healthy older adults.

Interplay between Developmental Flexibility and Determinism in the Evolution of Mimetic Heliconius Wing Patterns.

To what extent can we predict how evolution occurs? Do genetic architectures and developmental processes canalize the evolution of similar outcomes in a predictable manner? Or do historical contingencies impose alternative pathways to answer the same challenge? Examples of Müllerian mimicry between distantly related butterfly species provide natural replicates of evolution, allowing us to test whether identical wing patterns followed parallel or novel trajectories. Here, we explore the role that the signaling ligand WntA plays in generating mimetic wing patterns in Heliconius butterflies, a group with extraordinary mimicry-related wing pattern diversity. The radiation is relatively young, and numerous cases of wing pattern mimicry have evolved within the last 2.5-4.5 Ma. WntA is an important target of natural selection and is one of four major effect loci that underlie much of the pattern variation in the group. We used CRISPR/Cas9 targeted mutagenesis to generate WntA-deficient wings in 12 species and a further 10 intraspecific variants, including three co-mimetic pairs. In all tested butterflies, WntA knockouts affect pattern broadly and cause a shift among every possible scale cell type. Interestingly, the co-mimics lacking WntA were very different, suggesting that the gene networks that pattern a wing have diverged considerably among different lineages. Thus, although natural selection channeled phenotypic convergence, divergent developmental contexts between the two major Heliconius lineages opened different developmental routes to evolve resemblance. Consequently, even under very deterministic evolutionary scenarios, our results underscore a surprising unpredictability in the developmental paths underlying convergence in a recent radiation.

Potential Dietary Contributions From Rice and Wheat Flour Fortification in the Solomon Islands: Results From the 2012-2013 Household Income and Expenditure Survey.

BACKGROUND: Solomon Islands (SI) mandated wheat flour fortification in 2010. Rice is a key staple food in SI, and its fortification may provide an opportunity to deliver additional micronutrients to the population. OBJECTIVE: To determine whether fortified rice (proposed) and fortified wheat flour potentially benefit women of reproductive age (WRA). METHODS: We analyzed data from the 2012-2013 Household Income and Expenditure Survey to quantify food purchases, which served as a proxy for food consumption. We accounted for varied household composition by using adult male equivalent (AME) adjustments. RESULTS: Among 4478 households, 95.6% purchased rice and 86.6% purchased at least 1 food containing fortified wheat flour in the previous 14 days. Median apparent intake of rice among WRA was 205 g/d/AME. If fortified according to proposed standards, this apparent intake could result in the consumption of 12.3 mg iron/d, fulfilling 44% of the estimated average requirement (EAR), and 226 µg folic acid/d, satisfying 57% of World Health Organization's recommended intake of 400 µg/d. Overall, apparent rice consumption could fulfill 113%, 114%, and 131% of the EAR for WRA for zinc, thiamin, and niacin, respectively. Fortified wheat flour was consumed in much lower quantities, with an estimated apparent median intake of 22 g/d/AME among WRA and 78 g/d/AME among women in urban populations. CONCLUSIONS: The potential benefit of fortified wheat flour in SI is likely limited to urban populations. Apparent consumption of fortified rice in SI could contribute considerably to daily intake of iron, B vitamins including folic acid, and zinc among WRA.

Acute Kidney Injury Masked by Malnutrition: A Case Report and the Problem of Protein.

Acute kidney injury (AKI) is common among critically ill patients. There are a number of nutrition considerations in the management of AKI, including fluid balance, electrolyte and acid-base disturbances, protein provision, and management of comorbid conditions. The optimal amount of protein provision for patients with AKI who are not on renal replacement therapy (RRT) has been a topic of debate for years. Excessive protein provision may contribute to azotemia in these patients, but inadequate protein intake may harm nutrition status and result in poorer clinical outcomes. This review discusses a patient case of AKI masked by malnutrition and muscle loss and reviews the current literature on optimal protein intake in AKI (not on RRT). Based on a structured search strategy, 4 articles were reviewed. We conclude that the available evidence suggests that significant restrictions in protein intake are not necessary for those critically ill patients with AKI. However, the studies reviewed here showed significant heterogeneity in protein dose and delivery, estimation of protein needs, patient population, and definition of AKI, and thus further research is needed to systematically determine the optimal dose of protein for critically ill adults with AKI.

Maintenance DFMO Increases Survival in High Risk Neuroblastoma.

High risk neuroblastoma (HRNB) accounts for 15% of all pediatric cancer deaths. Despite aggressive therapy approximately half of patients will relapse, typically with only transient responses to second-line therapy. This study evaluated the ornithine decarboxylase inhibitor difluoromethylornithine (DFMO) as maintenance therapy to prevent relapse following completion of standard therapy (Stratum 1) or after salvage therapy for relapsed/refractory disease (Stratum 2). This Phase II single agent, single arm multicenter study enrolled from June 2012 to February 2016. Subjects received 2 years of oral DFMO (750 ± 250 mg/m2 twice daily). Event free survival (EFS) and overall survival (OS) were determined on an intention-to-treat (ITT) basis. 101 subjects enrolled on Stratum 1 and 100 were eligible for ITT analysis; two-year EFS was 84% (±4%) and OS 97% (±2%). 39 subjects enrolled on Stratum 2, with a two-year EFS of 54% (±8%) and OS 84% (±6%). DFMO was well tolerated. The median survival time is not yet defined for either stratum. DFMO maintenance therapy for HRNB in remission is safe and associated with high EFS and OS. Targeting ODC represents a novel therapeutic mechanism that may provide a new strategy for preventing relapse in children with HRNB.

Molecular Guided Therapy Provides Sustained Clinical Response in Refractory Choroid Plexus Carcinoma.

Choroid plexus carcinomas (CPCs) are rare, aggressive pediatric brain tumors with no established curative therapy for relapsed disease, and poor survival rates. TP53 Mutation or dysfunction correlates with poor or no survival outcome in CPCs. Here, we report the case of a 4 month-old female who presented with disseminated CPC. After initial response to tumor resection and adjuvant-chemotherapy, the tumor recurred and metastasized with no response to aggressive relapse therapy suggesting genetic predisposition. This patient was then enrolled to a Molecular Guided Therapy Clinical Trial. Genomic profiling of patient tumor and normal sample identified a TP53 germline mutation with loss of heterozygosity, somatic mutations including IDH2, and aberrant activation of biological pathways. The mutations were not targetable for therapy. However, targeting the altered biological pathways (mTOR, PDGFRB, FGF2, HDAC) guided identification of possibly beneficial treatment with a combination of sirolimus, thalidomide, sunitinib, and vorinostat. This therapy led to 92% reduction in tumor size with no serious adverse events, excellent quality of life and long term survival.

Long-term test-retest reliability of the California Verbal Learning Test - second edition.

OBJECTIVE: Aging is often associated with declines in episodic memory. Reliable tracking of memory requires assessment instruments that are stable over time to better understand changes potentially attributable to neurodegenerative disease. While prior studies support the test-retest reliability of memory instruments over brief intervals, follow-up testing in clinical settings typically occurs at least one-year later. The present study evaluated the long-term test-retest reliability of the California Verbal Learning Test - second edition (CVLT-2), a widely used measure of episodic learning and memory. METHOD: One hundred and fifty seven healthy older adults (mean age = 68.47 years; education = 17.28 years) underwent repeat assessment at an average of 1.30 years apart. Participants underwent repeat assessment using either parallel or alternate forms at follow-up. We utilized a standardized regression-based (SRB) approach to determine statistically significant changes in test scores over time. RESULTS: This study revealed modest 1-year test-retest correlation coefficients for the primary CVLT-2 measures (range = .57-.69) Results of SRB formulae are provided to assist clinicians with defining clinically relevant cognitive change on the CVLT-2 while controlling for confounding factors. CONCLUSIONS: Findings from this study support repeat test administration of the CVLT-2 over longer periods, and may enhance its applicability in determining longitudinal change in memory performance.

White matter hyperintensities correlate to cognition and fiber tract integrity in older adults with HIV.

Our aim was to examine the clinical relevance of white matter hyperintensities (WMH) in HIV. We used an automated approach to quantify WMH volume in HIV seropositive (HIV+; n = 65) and HIV seronegative (HIV-; n = 29) adults over age 60. We compared WMH volumes between HIV+ and HIV- groups in cross-sectional and multiple time-point analyses. We also assessed correlations between WMH volumes and cardiovascular, HIV severity, cognitive scores, and diffusion tensor imaging variables. Serostatus groups did not differ in WMH volume, but HIV+ participants had less cerebral white matter (mean: 470.95 [43.24] vs. 497.63 [49.42] mL, p = 0.010). The distribution of WMH volume was skewed in HIV+ with a high proportion (23%) falling above the 95th percentile of WMH volume defined by the HIV- group. Serostatus groups had similar amount of WMH volume growth over time. Total WMH volume directly correlated with measures of hypertension and inversely correlated with measures of global cognition, particularly in executive functioning, and psychomotor speed. Greater WMH volume was associated with poorer brain integrity measured from diffusion tensor imaging (DTI) in the corpus callosum and sagittal stratum. In this group of HIV+ individuals over 60, WMH burden was associated with cardiovascular risk and both worse diffusion MRI and cognition. The median total burden did not differ by serostatus; however, a subset of HIV+ individuals had high WMH burden.

A Diagnostic Dilemma: Similarity of Neuroradiological Findings in Central Nervous System Hemophagocytic Lymphohistiocytosis and Aspergillosis.

Central nervous system (CNS) involvement in the context of hemophagocytic lymphohistiocytosis (HLH) is not uncommon. Given the immunosuppressive nature of HLH therapy, infectious complications are also seen. We describe a 9-year-old male who developed acute neurological decline secondary to aspergillosis while undergoing HLH therapy. The significant overlap observed in CNS neuroimaging of HLH and aspergillosis and the subtleties that may help differentiate the two are discussed. The importance of obtaining tissue for definitive diagnosis is underscored.

Mild Cognitive Impairment is Associated With White Matter Integrity Changes in Late-Myelinating Regions Within the Corpus Callosum.

Degenerative brain changes in Alzheimer's disease may occur in reverse order of normal brain development based on the retrogenesis model. This study tested whether evidence of reverse myelination was observed in mild cognitive impairment (MCI) using a data-driven analytic approach based on life span developmental data. Whole-brain high-resolution diffusion tensor imaging scans were obtained for 31 patients with MCI and 79 demographically matched healthy older adults. Comparisons across corpus callosum (CC) regions of interest (ROIs) showed decreased fractional anisotropy (FA) in the body but not in the genu or splenium; early-, middle-, and late-myelinating ROIs restricted to the CC revealed decreased FA in late- but not early- or middle-myelinating ROIs. Voxelwise group differences revealed areas of lower FA in MCI, but whole-brain differences were equally distributed across early-, middle-, and late-myelinating regions. Overall, results within the CC support the retrogenesis model, although caution is needed when generalizing these results beyond the CC.

Glucose Dysregulation Interacts With APOE-∊4 to Potentiate Temporoparietal Cortical Thinning.

We examined the interactive effects of apolipoprotein ∊4 (APOE-∊4), a risk factor for Alzheimer's disease (AD), and diabetes risk on cortical thickness among 107 healthy elderly participants; in particular, participants included 27 APOE-∊4+ and 80 APOE-∊4- controls using T1-weighted structural magnetic resonance imaging. Regions of interests included select frontal, temporal, and parietal cortical regions. Among APOE-∊4, glucose abnormalities independently predicted reduced cortical thickness among temporoparietal regions but failed to predict changes for noncarriers. However, among noncarriers, age independently predicted reduced cortical thickness among temporoparietal and frontal regions. Diabetes risk is particularly important for the integrity of cortical gray matter in APOE-∊4 and demonstrates a pattern of thinning that is expected in preclinical AD. However, in the absence of this genetic factor, age confers risk for reduced cortical thickness among regions of expected compromise. This study supports aggressive management of cerebrovascular factors and earlier preclinical detection of AD among individuals presenting with genetic and metabolic risks.

Increased subcortical neural activity among HIV+ individuals during a lexical retrieval task.

BACKGROUND: Deficits in lexical retrieval, present in approximately 40% of HIV+ patients, are thought to reflect disruptions to frontal-striatal functions and may worsen with immunosuppression. Coupling frontal-striatal tasks such as lexical retrieval with functional neuroimaging may help delineate the pathophysiologic mechanisms underlying HIV-associated neurological dysfunction. OBJECTIVE: We examined whether HIV infection confers brain functional changes during lexical access and retrieval. It was expected that HIV+ individuals would demonstrate greater brain activity in frontal-subcortical regions despite minimal differences between groups on neuropsychological testing. Within the HIV+ sample, we examined associations between indices of immunosuppression (recent and nadir CD4+ count) and task-related signal change in frontostriatal structures. Method16 HIV+ participants and 12 HIV- controls underwent fMRI while engaged in phonemic/letter and semantic fluency tasks. Participants also completed standardized measures of verbal fluency RESULTS: HIV status groups performed similarly on phonemic and semantic fluency tasks prior to being scanned. fMRI results demonstrated activation differences during the phonemic fluency task as a function of HIV status, with HIV+ individuals demonstrating significantly greater activation in BG structures than HIV- individuals. There were no significant differences in frontal brain activation between HIV status groups during the phonemic fluency task, nor were there significant brain activation differences during the semantic fluency task. Within the HIV+ group, current CD4+ count, though not nadir, was positively correlated with increased activity in the inferior frontal gyrus and basal ganglia. CONCLUSION: During phonemic fluency performance, HIV+ patients recruit subcortical structures to a greater degree than HIV- controls despite similar task performances suggesting that fMRI may be sensitive to neurocompromise before overt cognitive declines can be detected. Among HIV+ individuals, reduced activity in the frontal-subcortical structures was associated with lower CD4+ count.

Anoikis-resistant subpopulations of human osteosarcoma display significant chemoresistance and are sensitive to targeted epigenetic therapies predicted by expression profiling.

BACKGROUND: Osteosarcoma (OS) is the most common type of solid bone cancer, with latent metastasis being a typical mode of disease progression and a major contributor to poor prognosis. For this to occur, cells must resist anoikis and be able to recapitulate tumorigenesis in a foreign microenvironment. Finding novel approaches to treat osteosarcoma and target those cell subpopulations that possess the ability to resist anoikis and contribute to metastatic disease is imperative. Here we investigate anchorage-independent (AI) cell growth as a model to better characterize anoikis resistance in human osteosarcoma while using an expression profiling approach to identify and test targetable signaling pathways. METHODS: Established human OS cell lines and patient-derived human OS cell isolates were subjected to growth in either adherent or AI conditions using Ultra-Low Attachment plates in identical media conditions. Growth rate was assessed using cell doubling times and chemoresistance was assessed by determining cell viability in response to a serial dilution of either doxorubicin or cisplatin. Gene expression differences were examined using quantitative reverse-transcription PCR and microarray with principal component and pathway analysis. In-vivo OS xenografts were generated by either subcutaneous or intratibial injection of adherent or AI human OS cells into athymic nude mice. Statistical significance was determined using student's t-tests with significance set at α=0.05. RESULTS: We show that AI growth results in a global gene expression profile change accompanied by significant chemoresistance (up to 75 fold, p<0.05). AI cells demonstrate alteration of key mediators of mesenchymal differentiation (ß-catenin, Runx2), stemness (Sox2), proliferation (c-myc, Akt), and epigenetic regulation (HDAC class 1). AI cells were equally tumorigenic as their adherent counterparts, but showed a significantly decreased rate of growth in-vitro and in-vivo (p<0.05). Treatment with the pan-histone deacetylase inhibitor vorinostat and the DNA methyltransferase inhibitor 5-azacytidine mitigated AI growth, while 5-azacytidine sensitized anoikis-resistant cells to doxorubicin (p<0.05). CONCLUSIONS: These data demonstrate remarkable plasticity in anoikis-resistant human osteosarcoma subpopulations accompanied by a rapid development of chemoresistance and altered growth rates mirroring the early stages of latent metastasis. Targeting epigenetic regulation of this process may be a viable therapeutic strategy.