Non-invasive Window Research Articles

Urinary Exosomes as Noninvasive Window to Glomerular and Tubular Cells and Their Communication

Urinary Exosomes as Noninvasive Window to Glomerular and Tubular Cells and Their Communication

Breath and Sputum Analyses in Asthmatic Patients: An Overview.

Recent advancements in asthma management include non-invasive methodologies such as sputum analysis, exhaled breath condensate (EBC), and fractional exhaled nitric oxide (FeNO). These techniques offer a means to assess airway inflammation, a critical feature of asthma, without invasive procedures. Sputum analysis provides detailed insights into airway inflammation patterns and cellular composition, guiding personalized treatment strategies. EBC collection, reflecting bronchoalveolar lining fluid composition, provides a non-invasive window into airway physiology. FeNO emerges as a pivotal biomarker, offering insights into eosinophilic airway inflammation and aiding in asthma diagnosis, treatment monitoring, and the prediction of exacerbation risks. Despite inherent limitations, each method offers valuable tools for a more comprehensive assessment of asthma. Combining these techniques with traditional methods like spirometry may lead to more personalized treatment plans and improved patient outcomes. Future research is crucial to refine protocols, validate biomarkers, and establish comprehensive guidelines in order to enhance asthma management with tailored therapeutic strategies and improved patient outcomes.

Exploring the biological basis of CT imaging features in pancreatic neuroendocrine tumors: a two-center study

Objective. Medical imaging offered a non-invasive window to visualize tumors, with radiomics transforming these images into quantitative data for tumor phenotyping. However, the intricate web linking imaging features, clinical endpoints, and tumor biology was mostly uncharted. This study aimed to unravel the connections between CT imaging features and clinical characteristics, including tumor histopathological grading, clinical stage, and endocrine symptoms, alongside immunohistochemical markers of tumor cell growth, such as the Ki-67 index and nuclear mitosis rate. Approach. We conducted a retrospective analysis of data from 137 patients with pancreatic neuroendocrine tumors who had undergone contrast-enhanced CT scans across two institutions. Our study focused on three clinical factors: pathological grade, clinical stage, and endocrine symptom status, in addition to two immunohistochemical markers: the Ki-67 index and the rate of nuclear mitosis. We computed both predefined (2D and 3D) and learning-based features (via sparse autoencoder, or SAE) from the scans. To unearth the relationships between imaging features, clinical factors, and immunohistochemical markers, we employed the Spearman rank correlation along with the Benjamini-Hochberg method. Furthermore, we developed and validated radiomics signatures to foresee these clinical factors. Main results. The 3D imaging features showed the strongest relationships with clinical factors and immunohistochemical markers. For the association with pathological grade, the mean absolute value of the correlation coefficient (CC) of 2D, SAE, and 3D features was 0.3318 ± 0.1196, 0.2149 ± 0.0361, and 0.4189 ± 0.0882, respectively. While for the association with Ki-67 index and rate of nuclear mitosis, the 3D features also showed higher correlations, with CC as 0.4053 ± 0.0786 and 0.4061 ± 0.0806. In addition, the 3D feature-based signatures showed optimal performance in clinical factor prediction. Significance. We found relationships between imaging features, clinical factors, and immunohistochemical markers. The 3D features showed higher relationships with clinical factors and immunohistochemical markers.

EEG-based major depressive disorder recognition by neural oscillation and asymmetry.

Major Depressive Disorder (MDD) is a pervasive mental health issue with significant diagnostic challenges. Electroencephalography (EEG) offers a non-invasive window into the neural dynamics associated with MDD, yet the diagnostic efficacy is contingent upon the appropriate selection of EEG features and brain regions. In this study, resting-state EEG signals from both eyes-closed and eyes-open conditions were analyzed. We examined band power across various brain regions, assessed the asymmetry of band power between the hemispheres, and integrated these features with clinical characteristics of MDD into a diagnostic regression model. Regression analysis found significant predictors of MDD to be beta2 (16-24 Hz) power in the Prefrontal Cortex (PFC) with eyes open (B = 20.092, p = 0.011), beta3 (24-40 Hz) power in the Medial Occipital Cortex (MOC) (B = -12.050, p < 0.001), and beta2 power in the Right Medial Frontal Cortex (RMFC) with eyes closed (B = 24.227, p < 0.001). Asymmetries in beta1 (12-16 Hz) power with eyes open (B = 28.047, p = 0.018), and in alpha (8-12 Hz, B = 9.004, p = 0.013) and theta (4-8 Hz, B = -13.582, p = 0.008) with eyes closed were also significant predictors. The study confirms the potential of multi-region EEG analysis in improving the diagnostic precision for MDD. By including both neurophysiological and clinical data, we present a more robust approach to understanding and identifying this complex disorder. The research is limited by the sample size and the inherent variability in EEG signal interpretation. Future studies with larger cohorts and advanced analytical techniques are warranted to validate and refine these findings.

Ocular Biomarkers in Alzheimer's Disease: Insights into Early Detection Through Eye-Based Diagnostics - A Literature Review.

Alzheimer's Disease (AD) is a significant challenge in neurodegenerative disorders, characterized by a gradual decline in cognitive functions. Diagnosis typically occurs at advanced stages when therapeutic options are less effective, underscoring the importance of early detection. Traditional diagnostic methods are often invasive and costly, spurring interest in more accessible and economical alternatives. The eye, as a direct link to the brain through the optic nerve, suggests that ocular changes could serve as early indicators of AD. This has led to the exploration of non-invasive ocular diagnostic tools. Technologies such as Optical Coherence Tomography (OCT), OCT Angiography (OCT-A), pupillometry, and eye-tracking, along with electrophysiological methods like Electroretinography (ERG) and Pattern Electroretinography (PEV), are being utilized to investigate potential ocular biomarkers. Further, tear fluid analysis has suggested that presence of amyloid-beta (Aβ) protein might reflect neurogenerative processes, providing a non-invasive window into disease progression. Exploring ocular changes as potential early indicators of Alzhei-mer's Disease (AD), we aimed to provide an overview of promising biomarkers for earlier diagnosis and intervention. Our review further investigates the connections between AD and other ocular degenera-tive diseases such as age-related macular degeneration (AMD) and glaucoma, uncovering shared pathogenic pathways that could offer new therapeutic targets. To establish the sensitivity and specificity of these ocular biomarkers, comprehensive studies are required. Moreover, larger, longitudinal studies are essential to confirm the effectiveness of ocular assessments in the preemptive diagnosis of Alzheimer's Disease.

Circulating Tumor Cells as Predictive and Prognostic Biomarkers in Solid Tumors.

Circulating tumor cells (CTCs) have emerged as pivotal biomarkers with significant predictive and prognostic implications in solid tumors. Their presence in peripheral blood offers a non-invasive window into the dynamic landscape of cancer progression and treatment response. This narrative literature review synthesizes the current state of knowledge surrounding the multifaceted role of CTCs in predicting clinical outcomes and informing prognosis across a spectrum of solid tumor malignancies. This review delves into the evolving landscape of CTC-based research, emphasizing their potential as early indicators of disease recurrence, metastatic potential, and therapeutic resistance. Moreover, we have underscored the dynamic nature of CTCs and their implications for personalized medicine. A descriptive and critical analysis of CTC detection methodologies, their clinical relevance, and their associated challenges is also presented, with a focus on recent advancements and emerging technologies. Furthermore, we examine the integration of CTC-based liquid biopsies into clinical practice, highlighting their role in guiding treatment decisions, monitoring treatment efficacy, and facilitating precision oncology. This review highlights the transformative impact of CTCs as predictive and prognostic biomarkers in the management of solid tumors by promoting a deeper understanding of the clinical relevance of CTCs and their role in advancing the field of oncology.

Potential Retinal Biomarkers in Alzheimer's Disease.

Alzheimer's disease (AD) represents a major diagnostic challenge, as early detection is crucial for effective intervention. This review examines the diagnostic challenges facing current AD evaluations and explores the emerging field of retinal alterations as early indicators. Recognizing the potential of the retina as a noninvasive window to the brain, we emphasize the importance of identifying retinal biomarkers in the early stages of AD. However, the examination of AD is not without its challenges, as the similarities shared with other retinal diseases introduce complexity in the search for AD-specific markers. In this review, we address the relevance of using the retina for the early diagnosis of AD and the complex challenges associated with the search for AD-specific retinal biomarkers. We provide a comprehensive overview of the current landscape and highlight avenues for progress in AD diagnosis by retinal examination.

Auditory brainstem mechanisms likely compensate for self-imposed peripheral inhibition

Feedback networks in the brain regulate downstream auditory function as peripheral as the cochlea. However, the upstream neural consequences of this peripheral regulation are less understood. For instance, the medial olivocochlear reflex (MOCR) in the brainstem causes putative attenuation of responses generated in the cochlea and cortex, but those generated in the brainstem are perplexingly unaffected. Based on known neural circuitry, we hypothesized that the inhibition of peripheral input is compensated for by positive feedback in the brainstem over time. We predicted that the inhibition could be captured at the brainstem with shorter (1.5 s) than previously employed long duration (240 s) stimuli where this inhibition is likely compensated for. Results from 16 normal-hearing human listeners support our hypothesis in that when the MOCR is activated, there is a robust reduction of responses generated at the periphery, brainstem, and cortex for short-duration stimuli. Such inhibition at the brainstem, however, diminishes for long-duration stimuli suggesting some compensatory mechanisms at play. Our findings provide a novel non-invasive window into potential gain compensation mechanisms in the brainstem that may have implications for auditory disorders such as tinnitus. Our methodology will be useful in the evaluation of efferent function in individuals with hearing loss.

Abstract 1053: Circulating tumor DNA from cerebrospinal fluid (CSF) allows for characterization and monitoring of glioma patients

Abstract Intro: High-Grade Gliomas (HGGs) are the most common and aggressive primary brain tumors in adults and are almost always fatal. Liquid biopsy provides a noninvasive window into the cancer genome and the underlying biology of the tumor. Circulating-tumor DNA (ctDNA) is a versatile analyte for tumor diagnosis, monitoring treatment response, detecting resistance, and tracking tumor evolution. The central hypothesis of our work is that detection of cerebrospinal fluid (CSF) ctDNA correlates with clinically significant events and can be used as a surrogate for tissue biopsy to guide treatment decisions in the clinic. Methods: Our study includes CSF ctDNA samples from 140 recurrent glioma patients at Memorial Sloan Kettering Cancer Center who underwent collection of CSF as part of their clinical evaluation for neurological signs and symptoms. For each patient, glioma subtype and grade were confirmed by a neuropathologist. Overall survival was calculated as the time interval between the date of diagnosis and the date of death. All samples were sequenced using the MSK-IMPACT targeted sequencing assay (468 genes). Allele-specific copy number calls were assessed using the FACETS algorithm. Mutations were classified as drivers based on OncoKB. To evaluate the relationship between CSF ctDNA detection and clinico-pathologic correlates, CSF ctDNA status was determined positive by the presence of at least one somatic mutation and CSF ctDNA status was correlated with clinico-pathologic features. Results: Within this cohort, we found 68 CSF ctDNA positive and 72 CSF negative samples. The most frequently mutated genes were: TERT (58.2%), TP53 (47.8%), IDH1 (20.9%) and EGFR (26.9%). We observed a concordance between contemporaneously sampled tumor and CSF. In a multivariate analysis accounting for established prognostic factors including: % extent of resection at diagnosis; tumor burden at the time of lumbar puncture; and IDH status, we found that CSF ctDNA positivity was negatively correlated with overall survival (HR: 2.52, p &amp;lt;0.0001). Patients with CSF positive samples had an overall survival of 3.35 months vs 11.91 months for those with CSF negative samples (p &amp;lt; 0.0001). Conclusion: ctDNA from CSF depicts a powerful analyte with the potential to alter the standard of care. We have established a robust liquid biopsy program across the neuro-oncology department at MSK, and MSK-IMPACT is now certified by NYS DOH for use on CSF ctDNA enabling routine integration into clinical care. In summary, we are now able to monitor the changing genome along the disease course and have the potential to detect disease occurrence at an earlier time point, however further validation of CSF ctDNA for disease monitoring is needed. Additionally, our data suggests that CSF ctDNA may be used as a prognostic biomarker for survival, but confirmation requires further validation in a prospective study. Citation Format: Subhiksha Nandakumar, Christoph Kreitzer, Charli Ann Hertz, Johnathan Rafailov, Timothy Song, Nicholas D. Socci, A. Rose Brannon, Maria E. Arcila, David B. Solit, Michael F. Berger, Nikolaus Schultz, Ingo K. Mellinghoff, Alexandra M. Miller. Circulating tumor DNA from cerebrospinal fluid (CSF) allows for characterization and monitoring of glioma patients [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1053.

A hitchhiker's guide to cell-free DNA biology.

Liquid biopsy provides a noninvasive window to the cancer genome and physiology. In particular, cell-free DNA (cfDNA) is a versatile analyte for guiding treatment, monitoring treatment response and resistance, tracking minimal residual disease, and detecting cancer earlier. Despite certain successes, brain cancer diagnosis is amongst those applications that has so far resisted clinical implementation. Recent approaches have highlighted the clinical gain achievable by exploiting cfDNA biological signatures to boost liquid biopsy or unlock new applications. However, the biology of cfDNA is complex, still partially understood, and affected by a range of intrinsic and extrinsic factors. This guide will provide the keys to read, decode, and harness cfDNA biology: the diverse sources of cfDNA in the bloodstream, the mechanism of cfDNA release from cells, the cfDNA structure, topology, and why accounting for cfDNA biology matters for clinical applications of liquid biopsy.

Pupil diameter tracked during motor adaptation in humans.

Pupil diameter, under constant illumination, is known to reflect individuals' internal states, such as surprise about observation and environmental uncertainty. Despite the growing use of pupillometry in cognitive learning studies as an additional measure for examining internal states, few studies have used pupillometry in human motor learning studies. Here, we provide the first detailed characterization of pupil diameter changes in a short-term reach adaptation paradigm. We measured pupil changes in 121 human participants while they adapted to abrupt, gradual, or switching force field conditions. Sudden increases in movement error caused by the introduction/reversal of the force field resulted in strong phasic pupil dilation during movement accompanied by a transient increase in tonic premovement baseline pupil diameter in subsequent trials. In contrast, pupil responses were reduced when the force field was gradually introduced, indicating that large, unexpected errors drove the changes in pupil responses. Interestingly, however, error-induced pupil responses gradually became insensitive after experiencing multiple force field reversals. We also found an association between baseline pupil diameter and incidental knowledge of the gradually introduced perturbation. Finally, in all experiments, we found a strong co-occurrence of larger baseline pupil diameter with slower reaction and movement times after each rest break. Collectively, these results suggest that tonic baseline pupil diameter reflects one's belief about environmental uncertainty, whereas phasic pupil dilation during movement reflects surprise about a sensory outcome (i.e., movement error), and both effects are modulated by novelty. Our results provide a new approach for nonverbally assessing participants' internal states during motor learning.NEW & NOTEWORTHY Pupil diameter is known as a noninvasive window into individuals' internal states. Despite the growing use of pupillometry in cognitive learning studies, it receives little attention in motor learning studies. Here, we characterized the pupil responses in a short-term reach adaptation paradigm by measuring pupil diameter of human participants while they adapted to abrupt, gradual, or switching force field conditions. Our results demonstrate how surprise and uncertainty reflected in pupil diameter develop during motor adaptation.

Quantitative Electroencephalogram (qEEG) as a Natural and Non-Invasive Window into Living Brain and Mind in the Functional Continuum of Healthy and Pathological Conditions

Many practicing clinicians are time-poor and are unaware of the accumulated neuroscience developments. Additionally, given the conservative nature of their field, key insights and findings trickle through into the mainstream clinical zeitgeist rather slowly. Over many decades, clinical, systemic, and cognitive neuroscience have produced a large and diverse body of evidence for the potential utility of brain activity (measured by electroencephalogram—EEG) for neurology and psychiatry. Unfortunately, these data are enormous and essential information often gets buried, leaving many researchers stuck with outdated paradigms. Additionally, the lack of a conceptual and unifying theoretical framework, which can bind diverse facts and relate them in a meaningful way, makes the whole situation even more complex. To contribute to the systematization of essential data (from the authors’ point of view), we present an overview of important findings in the fields of electrophysiology and clinical, systemic, and cognitive neuroscience and provide a general theoretical–conceptual framework that is important for any application of EEG signal analysis in neuropsychopathology. In this context, we intentionally omit detailed descriptions of EEG characteristics associated with neuropsychopathology as irrelevant to this theoretical–conceptual review.

Near-infrared Spectroscopy Estimation Of Combined Muscle Oxidative Capacity And Oxygen Diffusion Capacity In Humans

PURPOSE: Muscle oxygen uptake (mV̇O2) depends on both O2 supply (convective and diffusive O2 delivery) and O2 demand (ATP utilization rate and mitochondrial function). The mV̇O2 recovery rate constant (k) measured by near-infrared spectroscopy (NIRS), in the presence of non-limiting O2 availability, is associated with muscle oxidative capacity in vivo. However, when O2 availability is limiting, k may be limited by muscle O2 diffusing capacity (DmO2). We aimed to determine associations of: i) k obtained in different O2 availability conditions with ex vivo mitochondrial function and ii) the difference in k (∆k) between conditions of non-limiting and limiting O2 availability with capillary-to-fiber ratio (C:F). METHODS: 12 healthy participants volunteered (28 ± 5 yrs; V̇O2peak 37.1 ± 8.0 ml*kg-1*min-1). On visits 1 and 2, k of the vastus lateralis (VL) was measured by NIRS during 10-15 intermittent arterial occlusions performed immediately after moderate intensity constant work-rate exercise. The duration and timing of occlusions were manipulated to maintain TSI in a 10% range change either below (LOW) or above (HIGH) the mid-point of the functional range from a prolonged occlusion. ∆k is the difference between LOW and HIGH k measurements. On visit 3, the VL was biopsied to measure C:F and maximal O2 flux using saturating substrates for complexes I + II by high-resolution respirometry (HRR). RESULTS: O2 flux was 37.7 ± 10.6 and 56.8 ± 19.8 pmol*s-1*mg-1 wet weight in maximal ADP-stimulated phosphorylating state and maximal noncoupled state, respectively. C:F ratio ranged 2.15 to 2.49. k was greater in HIGH (3.15 ± 0.45 min-1) than in LOW (1.56 ± 0.79 min-1, p < 0.0001). k was significantly correlated with both HRR measurements in HIGH (r = 0.72 - 0.69), but not in LOW (r = -0.24 - -0.28). ∆k ranged -0.19 to -3.19 min-1, and was inversely correlated with C:F ratio (r = -0.68, p = 0.01). CONCLUSION: These data show that mV̇O2 recovery rate constant (k) reflected muscle oxidative capacity only under conditions of non-limiting O2 availability. Moreover, ∆k, obtained under different O2 availability conditions, was associated with C:F ratio, a mediator of DmO2. Thus, assessment of muscle k and ∆k using NIRS under HIGH and LOW TSI conditions provides a non-invasive window on both muscle oxidative capacity and muscle O2 diffusive capacity.

Quantum enabled functional neuroimaging: the why and how of magnetoencephalography using optically pumped magnetometers

ABSTRACT Non-invasive imaging has transformed neuroscientific discovery and clinical practice, providing a non-invasive window into the human brain. However, whilst techniques like MRI generate ever more precise images of brain structure, in many cases, it’s the function within neural networks that underlies disease. Here, we review the potential for quantum-enabled magnetic field sensors to shed light on such activity. Specifically, we describe how optically pumped magnetometers (OPMs) enable magnetoencephalographic (MEG) recordings with higher accuracy and improved practicality compared to the current state-of-the-art. The paper is split into two parts: first, we describe the work to date on OPM-MEG, detailing why this novel biomagnetic imaging technique is proving disruptive. Second, we explain how fundamental physics, including quantum mechanics and electromagnetism, underpins this developing technology. We conclude with a look to the future, outlining the potential for OPM-MEG to initiate a step change in the understanding and management of brain health.

Macular Vessel Density Measurement in Pediatric Renal and Liver Transplant

Microcirculatory dysfunction is known to be associated with organ failure and increased mortality in transplant patients. Noninvasive monitorization of retinal structures of the eye could be a predictor for systemic microvasculature in these patients. Therefore, in this study we aimed to evaluate the retinal microvascular changes in pediatric patients who had undergone liver or renal transplant surgery, using optical coherence tomography angiography. The medical records of pediatric patients who had liver or renal transplant in the past 10 years were reviewed. The macular vessel density parameters were obtained by optical coherence tomography angiography (Avanti RTVue XR). The results were compared with the age-matched, sex-matched, and spherical equivalent-matched healthy participants (control group). The IBM SPSS (version 25.0) statistics program was used for data analysis. We included 32 eyes of 16 liver transplant patients, 20 eyes of 10 renal transplant patients, and 64 eyes of 32 healthy participants (control group). Superficial macular whole image, superficial perifoveal, and deep foveal vessel densities were found to be lower in the liver transplant group compared with the healthy control group (P = .02, P = .01, and P = .01, respectively). Superficial foveal, deep macular whole image, deep foveal, and deep perifoveal vessel densities were found to be lower in the renal transplant group compared with the healthy control group (P = .03, P = .04, P = .01, and P = .02, respectively). Macular vessel density measurements are affected in pediatric renal and liver transplant patients. In those patients, retinal optical coherence tomography and optical coherence tomography angiography measurements may provide a noninvasive window to the microcirculation.

Predictive RNA profiles for early and very early spontaneous preterm birth

Spontaneous preterm birth remains the main driver of childhood morbidity and mortality. Because of an incomplete understanding of the molecular pathways that result in spontaneous preterm birth, accurate predictive markers and target therapeutics remain elusive. This study sought to determine if a cell-free RNA profile could reveal a molecular signature in maternal blood months before the onset of spontaneous preterm birth. Maternal samples (n=242) were obtained from a prospective cohort of individuals with a singleton pregnancy across 4 clinical sites at 12-24 weeks (nested case-control; n=46 spontaneous preterm birth <35 weeks and n=194 term controls). Plasma was processed via a next-generation sequencing pipeline for cell-free RNA using the Mirvie RNA platform. Transcripts that were differentially expressed in next-generation sequencing cases and controls were identified. Enriched pathways were identified in the Reactome database using overrepresentation analysis. Twenty five transcripts associated with an increased risk of spontaneous preterm birth were identified. A logistic regression model was developed using these transcripts to predict spontaneous preterm birth with an area under the curve=0.80 (95% confidence interval, 0.72-0.87) (sensitivity=0.76, specificity=0.72). The gene discovery and model were validated through leave-one-out cross-validation. A unique set of 39 genes was identified from cases of very early spontaneous preterm birth (<25 weeks, n=14 cases with time to delivery of 2.5±1.8 weeks); a logistic regression classifier on the basis of these genes yielded an area under the curve=0.76 (95% confidence interval, 0.63-0.87) in leave-one-out cross validation. Pathway analysis for the transcripts associated with spontaneous preterm birth revealed enrichment of genes related to collagen or the extracellular matrix in those who ultimately had a spontaneous preterm birth at <35 weeks. Enrichment for genes in insulin-like growth factor transport and amino acid metabolism pathways were associated with spontaneous preterm birth at <25 weeks. Second trimester cell-free RNA profiles in maternal blood provide a noninvasive window to future occurrence of spontaneous preterm birth. The systemic finding of changes in collagen and extracellular matrix pathways may serve to identify individuals at risk for premature cervical remodeling, with growth factor and metabolic pathways implicated more often in very early spontaneous preterm birth. The use of cell-free RNA profiles has the potential to accurately identify those at risk for spontaneous preterm birth by revealing the underlying pathophysiology, creating an opportunity for more targeted therapeutics and effective interventions.

Physiological and metabolic effects of healthy female aging on exhaled breath biomarkers

SummaryHealthy aging driven physio-metabolic events in females hold the key to complex in vivo mechanistic links and systemic cross talks. Effects from basic changes at genome, proteome, metabolome, and lipidome levels are often reflected at the upstream phenome (e.g., breath volatome) cascades. Here, we have analyzed exhaled volatile metabolites (measured via real time mass spectrometry based breathomics) data from 204 healthy females, aged between 07 and 80 years. Age related substance-specific differences were observed in breath biomarkers. Exhalation of blood-borne endogenous organosulfur, short-chain fatty acids, alcohols, aldehydes, alkene, ketones and exogenous nitriles, terpenes, and aromatics have denominated interplay between endocrine differences, energy homeostasis, systemic microbial diversity, oxidative stress, and lifestyle. Overall marker expressions were suppressed under daily oral contraception. Young homosexual/lesbian adults turned out as breathomic outliers. Previously proposed disease-specific breath biomarkers should be reevaluated upon aging effects. Breathomics offers a noninvasive window toward system-wide understanding and personalized monitoring of aging i.e., translatable to gerontology.

Clinical applications of brain diffusion-tensor imaging and fiber tractography

Background Diffusion-tensor imaging (DTI) and fiber tractography are relatively recent MRI techniques that have opened an entirely new noninvasive window on the white matter (WM) connectivity of the human brain. Since their introduction, they have rapidly evolved and found application in essentially every disorder involving the WM. Aim The aim of this work was to study the clinical applications of DTI and fiber tractography in various neoplastic and nonneoplastic brain lesions, as well as to demonstrate their role in preoperative mapping of WM tracts in relation to brain lesions. Patients and methods A prospective study was conducted for 2 years on 40 patients presenting to Alexandria University with variable intracranial lesions related to WM tracts who underwent DTI and fiber tractography. The study included 25 males and 15 females. The age of the patients ranged from 6 to 76 years (mean age, 40.7 years). Qualitative analysis of DTI data was performed using directionally encoded color maps and three-dimensional tractography reconstruction. Results According to visual analysis multiple projection, association and/or commissural WM fiber tracts were involved; the most common was the corticospinal tract in 25 (62.5%) cases. WM tract involvement patterns were deviated/splayed tracts in 31 (64.6%) cases, infiltrated in nine (18.8%) cases, edematous in five (10.4%) cases, and interrupted in three (6.3%) cases. Conclusion DTI and fiber tractography are valuable noninvasive techniques providing qualitative information aiding in lesion characterization, determining WM integrity, and essential in the surgical planning for patients with intrinsic brain lesions.

A Structured Approach to Test the Signal Quality of Electroencephalography Measurements During Use of Head-Mounted Displays for Virtual Reality Applications.

Joint applications of virtual reality (VR) systems and electroencephalography (EEG) offer numerous new possibilities ranging from behavioral science to therapy. VR systems allow for highly controlled experimental environments, while EEG offers a non-invasive window to brain activity with a millisecond-ranged temporal resolution. However, EEG measurements are highly susceptible to electromagnetic (EM) noise and the influence of EM noise of head-mounted-displays (HMDs) on EEG signal quality has not been conclusively investigated. In this paper, we propose a structured approach to test HMDs for EM noise potentially harmful to EEG measures. The approach verifies the impact of HMDs on the frequency- and time-domain of the EEG signal recorded in healthy subjects. The verification task includes a comparison of conditions with and without an HMD during (i) an eyes-open vs. eyes-closed task, and (ii) with respect to the sensory- evoked brain activity. The approach is developed and tested to derive potential effects of two commercial HMDs, the Oculus Rift and the HTC Vive Pro, on the quality of 64-channel EEG measurements. The results show that the HMDs consistently introduce artifacts, especially at the line hum of 50 Hz and the HMD refresh rate of 90 Hz, respectively, and their harmonics. The frequency range that is typically most important in non-invasive EEG research and applications (<50 Hz) however, remained largely unaffected. Hence, our findings demonstrate that high-quality EEG recordings, at least in the frequency range up to 50 Hz, can be obtained with the two tested HMDs. However, the number of commercially available HMDs is constantly rising. We strongly suggest to thoroughly test such devices upfront since each HMD will most likely have its own EM footprint and this article provides a structured approach to implement such tests with arbitrary devices.

Breathomics of Healthy Female Aging: Physio-Metabolic Effects of Puberty, Teenage, Reproductive and Postmenopausal Life on Exhaled Biomarkers

Healthy aging driven physio-metabolic events in female hold keys to complex in vivo mechanistic links and systemic cross-talks. Effects from basic changes at genome, proteome, metabolome and lipidome levels are often reflected at the up-stream phenome (e.g. breath volatome) cascades. Here, we have analyzed exhaled volatile metabolites (measured via real-time mass-spectrometry based breathomics) data from 204 healthy females, aged between 07 – 80 years. Age related substance-specific differences were observed in breath biomarkers. Exhalation of blood-borne endogenous organosulfur, short-chain fatty acids, alcohols, aldehydes, alkene, ketones and exogenous nitriles, terpenes and aromatics have denominated interplay between endocrine differences, energy homeostasis, systemic microbial diversity, oxidative stress and lifestyle. Overall marker expressions were suppressed under daily oral contraception. Young homosexual/lesbian adults turned out as breathomics outliers. Previously proposed disease-specific breath biomarkers should be re-evaluated upon aging effects. Breathomics offers a non-invasive window towards system-wide understanding and personalized monitoring of aging i.e. translatable to gerontology.