Publications by authors named "Fenghua Tian"

61 Publications

Complete Genomic Characterization and Identification of sp. nov., a Novel Pathogen Causes Yellow Rot Disease on .

J Fungi (Basel) 2021 Aug 28;7(9). Epub 2021 Aug 28.

Engineering Research Center of Chinese Ministry of Education for Edible and Medicinal Fungi, Jilin Agricultural University, Changchun 130118, China.

"Hongtuozhusun" () is an important edible and medicinal mushroom endemic to Southwest China. However, yellow rot disease is a severe disease of . that occurs extensively in Guizhou Province. It has caused major economic losses and hinders the development of the . industry. In this study, 28 microorganism strains were isolated from diseased fruiting bodies of at various stages, two of which were confirmed to be pathogenic based on Koch's postulates. These two strains are introduced herein as sp. nov. based on morphological, physiological, and molecular analysis. We reported a high-quality de novo sequencing and assembly of the . genome using single-molecule real-time sequencing technology. The whole genome was approximately 14.148 Mb with a G+C content of 43.55%. Genome assembly generated 8 contigs with an N50 length of 1,822,654 bp. The genome comprised 5966 annotated protein-coding genes. This is the first report of mushroom disease caused by species. We expect that the information on genome properties, particularly in pathogenicity-related genes, assist in developing effective control measures in order to prevent severe losses and make amendments in management strategies.
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http://dx.doi.org/10.3390/jof7090707DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8468998PMC
August 2021

Genomic Analysis of Reveals the Basis of Its Medicinal Properties and Evolutionary Relationships.

Front Microbiol 2021 1;12:652324. Epub 2021 Jul 1.

Engineering Research Center of Chinese Ministry of Education for Edible and Medicinal Fungi, Jilin Agricultural University, Changchun, China.

Yuanmo [ (Y.C. Dai, Niemelä & G.F. Qin) T. Saito, Tonouchi & T. Harada] is an important edible and medicinal mushroom endemic to Northeastern China. Here we report the sequencing and assembly of the genome using single-molecule real-time sequencing technology. The whole genome was approximately 35.65 Mb, with a G + C content of 48.31%. Genome assembly generated 41 contigs with an N50 length of 1,772,559 bp. The genome comprised 9,364 annotated protein-coding genes, many of which encoded enzymes involved in the modification, biosynthesis, and degradation of glycoconjugates and carbohydrates or enzymes predicted to be involved in the biosynthesis of secondary metabolites such as terpene, type I polyketide, siderophore, and fatty acids, which are responsible for the pharmacodynamic activities of . We also identified genes encoding 1,3-β-glucan synthase and endo-1,3(4)-β-glucanase, which are involved in polysaccharide and uridine diphosphate glucose biosynthesis. Phylogenetic and comparative analyses of Basidiomycota fungi based on a single-copy orthologous protein indicated that the genus is an independent group that evolved from the Pleurotaceae family. The annotated whole-genome sequence of can serve as a reference for investigations of bioactive compounds with medicinal value and the development and commercial production of superior varieties.
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http://dx.doi.org/10.3389/fmicb.2021.652324DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8281127PMC
July 2021

Tracking Changes in Frontal Lobe Hemodynamic Response in Individual Adults With Developmental Language Disorder Following HD tDCS Enhanced Phonological Working Memory Training: An fNIRS Feasibility Study.

Front Hum Neurosci 2020 10;14:362. Epub 2020 Sep 10.

School of Behavioral and Brain Sciences, The University of Texas at Dallas, Dallas, TX, United States.

Current research suggests a neurobiological marker of developmental language disorder (DLD) in adolescents and young adults may be an atypical neural profile coupled with behavioral performance that overlaps with that of normal controls. Although many imaging techniques are not suitable for the study of speech and language processing in DLD populations, fNIRS may be a viable option. In this study we asked if fNIRS can be used to identify atypical cortical activation patterns in individual adults with DLD and track potential changes in cortical activation patterns following a phonological working memory training protocol enhanced with anodal HD tDCS stimulation to the presupplementary motor area (preSMA). The purpose of this study was two-fold: (1) to determine if fNIRS can be used to identify atypical hemodynamic responses in individual young adults with DLD during active spoken word processing and, (2) to determine if fNIRS can detect changes in hemodynamic response in these same adults with DLD following anodal HD tDCS enhanced phonological working memory training. Two adult subjects with DLD (female, age 25) completed a total of two sessions of fNIRs working memory task prior to and following one session of a non-word repetition task paired with anodal HD tDCS (1.0 mA tDCS; 20 min) to the preSMA. Standardized -scores of behavioral measures (accuracy and reaction time) and changes in hemodynamic response during an n-back working memory task for the two participants with DLD was compared to that of a normative sample of 21 age- and gender- matched normal controls (ages 18 to 25) prior to and following phonological working memory training. Individual standardized -scores for each participant with DLD indicated that prior to training, hemoglobin response in the prefrontal lobe for both participants was markedly different from each other and normal controls. Following training, standard scores showed that the hemodynamic response for both participants moved within normal limits for ROIs. These findings highlight the feasibility of fNIRS to establish individual differences in the link between behavior and neural patterns in single subjects with DLD, as well as track individual differences in changes in brain activity following working memory training.
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http://dx.doi.org/10.3389/fnhum.2020.00362DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7511756PMC
September 2020

Neural Networks to Predict Radiographic Brain Injury in Pediatric Patients Treated with Extracorporeal Membrane Oxygenation.

J Clin Med 2020 Aug 22;9(9). Epub 2020 Aug 22.

Children's Health Dallas, Dallas, TX 75201, USA.

Brain injury is a significant source of morbidity and mortality for pediatric patients treated with Extracorporeal Membrane Oxygenation (ECMO). Our objective was to utilize neural networks to predict radiographic evidence of brain injury in pediatric ECMO-supported patients and identify specific variables that can be explored for future research. Data from 174 ECMO-supported patients were collected up to 24 h prior to, and for the duration of, the ECMO course. Thirty-five variables were collected, including physiological data, markers of end-organ perfusion, acid-base homeostasis, vasoactive infusions, markers of coagulation, and ECMO-machine factors. The primary outcome was the presence of radiologic evidence of moderate to severe brain injury as established by brain CT or MRI. This information was analyzed by a neural network, and results were compared to a logistic regression model as well as clinician judgement. The neural network model was able to predict brain injury with an Area Under the Curve (AUC) of 0.76, 73% sensitivity, and 80% specificity. Logistic regression had 62% sensitivity and 61% specificity. Clinician judgment had 39% sensitivity and 69% specificity. Sequential feature group masking demonstrated a relatively greater contribution of physiological data and minor contribution of coagulation factors to the model's performance. These findings lay the foundation for further areas of research directions.
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http://dx.doi.org/10.3390/jcm9092718DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7565544PMC
August 2020

Cerebral Hemodynamic Profile in Ischemic and Hemorrhagic Brain Injury Acquired During Pediatric Extracorporeal Membrane Oxygenation.

Pediatr Crit Care Med 2020 10;21(10):879-885

Children's Health in Dallas, Dallas, TX.

Objectives: To describe the cerebral hemodynamic profiles associated with ischemic and hemorrhagic brain injury during neonatal and pediatric extracorporeal membrane oxygenation.

Design: A retrospective cohort study.

Setting: Tertiary PICU.

Patients: Forty-seven neonatal and pediatric patients (0-15 yr of age) placed on extracorporeal membrane oxygenation from January 2014 to December 2018.

Measurements And Main Results: Continuous monitoring of mean arterial pressure and cerebral tissue oxygen saturation was conducted through entire extracorporeal membrane oxygenation run. Wavelet analysis was performed to assess changes in cerebral autoregulation and to derive pressure-dependent autoregulation curves based on the mean arterial pressure and cerebral tissue oxygen saturation data. Patients were classified into three brain injury groups: no-injury, ischemic injury, and hemorrhagic injury based on neuroimaging results. No-injury patients (n = 23) had minimal variability in the autoregulation curve over a broad range of blood pressure. Ischemic injury (n = 16) was more common than hemorrhagic injury (n = 8), and the former was associated with increased mortality and morbidity. Ischemic group showed significant abnormalities in cerebral autoregulation in the lower blood pressure range, suggesting pressure-dependent cerebral perfusion. Hemorrhagic group had highest average blood pressure as well as the lowest cerebral tissue oxygenation saturation, suggesting elevated cerebral vascular resistance. Mean heparin dose during extracorporeal membrane oxygenation was lower in both ischemic and hemorrhagic groups compared with the no-injury group.

Conclusions: This study outlines distinct differences in underlying cerebral hemodynamics associated with ischemic and hemorrhagic brain injury acquired during extracorporeal membrane oxygenation. Real-time monitoring of cerebral hemodynamics in patients acquiring brain injury during extracorporeal membrane oxygenation can help optimize their management.
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http://dx.doi.org/10.1097/PCC.0000000000002438DOI Listing
October 2020

Rigor of Neurovascular Coupling (NVC) Assessment in Newborns Using Different Amplitude EEG Algorithms.

Sci Rep 2020 06 8;10(1):9183. Epub 2020 Jun 8.

Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX, USA.

Birth asphyxia constitutes a major global public health burden for millions of infants with a critical need for real time physiological biomarkers. This proof of concept study targets the translational rigor of such biomarkers and aims to examine whether the variability in the amplitude-integrated EEG (aEEG) outputs impact the determination of neurovascular coupling (NVC) in newborns with encephalopathy. A convenience sample with neonatal asphyxia were monitored for twenty hours in the first day of life with EEG and near infrared spectroscopy (NIRS)-based cerebral tissue oxygen saturation (SctO2). NVC between aEEG and NIRS-SctO2 was assessed using wavelet transform coherence (WTC) analysis, specifically by the wavelet total pixel number of significant coherences within 95% confidence interval. The raw EEG was converted to aEEG using three different methods: Method (M1) derives from the algorithm by Zhang and Ding. Method (M2) uses a Neonatal EEG Analysis Toolbox (WU-NEAT). Method (M3) extracts output directly from a commercial platform with an undisclosed algorithm. Our results demonstrate excellent agreement with Bland Altman comparisons for WTC-based NVC irrespective of the algorithms used, despite significant heterogeneities in the aEEG tracings produced by three algorithms. Our findings confirm the robustness of NVC wavelet analysis in Neonatal Encephalopathy related to HIE.
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http://dx.doi.org/10.1038/s41598-020-66227-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7280505PMC
June 2020

Regional heterogeneity of cerebral hemodynamics in mild neonatal encephalopathy measured with multichannel near-infrared spectroscopy.

Pediatr Res 2021 03 3;89(4):882-888. Epub 2020 Jun 3.

Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX, USA.

Background: Neuromonitoring at the bedside is the key to understand the pathophysiological mechanisms of brain injury associated with neonatal encephalopathy. The current practice is to monitor the forehead using a noninvasive cerebral oximetry-it remains unknown to what extent cerebral hemodynamics in other brain regions is different to the frontal region.

Method: A multichannel near-infrared spectroscopy (NIRS) system was used to monitor neonates (n = 14) with fetal acidosis and mild neonatal encephalopathy at four brain regions (the frontal, posterior, left temporal, and right temporal lobes). The data were compared to delineate the regional difference in (1) cerebral hemodynamics and (2) pressure autoregulation. For both analyses, wavelet transform coherence was applied.

Results: We observed frontal-posterior heterogeneity as indicated by significantly lower coherence between these two regions (p = 0.02). Furthermore, areas with regional magnetic resonance imaging (MRI)-detected lesions showed greater hemodynamic variations compared to non-affected areas (p = 0.03), while cerebral autoregulation was not affected and showed no difference.

Conclusion: Cerebral hemodynamics in mild neonatal encephalopathy is heterogeneous across different brain regions, while cerebral autoregulation remains intact. These findings indicate the robustness of the wavelet measure of cerebral autoregulation in this population, but need to be further investigated in the presence of severe injury.

Impact: This proof-of-concept study is the first to investigate the regional difference of cerebral hemodynamics and autoregulation in mild neonatal encephalopathy. Study findings confirm that brain functions are complex in the developing neonatal brain and that cerebral hemodynamics are region specific in newborns with frontal-posterior heterogeneity among brain regions probed by multichannel NIRS. Regional MRI lesions were associated with differences across NIRS regional channels among the affected side. Cerebral autoregulation with multichannel NIRS is not affected by regional MRI abnormalities.
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http://dx.doi.org/10.1038/s41390-020-0992-5DOI Listing
March 2021

Investigation of High-Power Properties of PIN-PMN-PT Relaxor-Based Ferroelectric Single Crystals and PZT-4 Piezoelectric Ceramics.

IEEE Trans Ultrason Ferroelectr Freq Control 2020 Aug 9;67(8):1641-1646. Epub 2020 Mar 9.

We developed a high-power piezoelectric characterization system that was used to study the high-field properties of (1-x-y)Pb(InNb)O-yPb(MgNb) O-xPbTiO (PIN-PMN-PT) relaxor ferroelectric single crystals and PZT-4 piezoelectric ceramics. The impedance spectrum of 31 modes was measured under constant voltage by the high-power piezoelectric system. From measuring the resonance and antiresonance frequencies, the high-field behaviors of the electromechanical coupling coefficients, elastic compliances, and piezoelectric coefficients of the PIN-PMN-PT crystals were determined and compared with commercial PZT ceramics. By fitting the equivalent circuit parameters under large electric fields, the mechanical quality factors of the PIN-PMN-PT single crystals and PZT-4 ceramics were calculated as well. The results showed that the mechanical quality factor of the PZT-4 is higher than that of PIN-PMN-PT, and the mechanical quality factors of the PZT-4 and PIN-PMN-PT both decrease sharply first and then decrease slowly with increasing the electric field. The tensile strengths of PIN-PMN-PT crystals and PZT-4 ceramics were also determined by the impedance method, where we found that the tensile strengths of PIN-PMN-PT crystal and PZT-4 ceramic were 19.6 and 76.4 MPa, respectively. The 31-mode vibrators of PIN-PMN-PT crystals and PZT-4 ceramics can be driven by the largest electric field of 33 and 65 V/mm under resonance frequency, respectively.
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http://dx.doi.org/10.1109/TUFFC.2020.2979217DOI Listing
August 2020

Transcriptomic profiling sheds light on the blue-light and red-light response of oyster mushroom (Pleurotus ostreatus).

AMB Express 2020 Jan 18;10(1):10. Epub 2020 Jan 18.

Department of Plant Protection, Jilin Agricultural University, Changchun, 130118, Jilin, China.

Blue light is an important environmental factor that induces mushroom primordium differentiation and fruiting body development. Although blue-light treatment has been applied for the production of oyster mushroom (Pleurotus ostreatus), the blue-light response mechanisms of P. ostreatus still remain unclear. In the present study, we exposed the primordium of P. ostreatus to blue-light, red-light, and dark conditions for 7 days. Subsequently, comparative transcriptomics analysis of the stipe, pileus, and gill under the three light conditions was performed to reveal the gene expression response mechanism of P. ostreatus to blue light and red light. The results showed that blue light enhanced the growth and development of all the three organs of P. ostreatus, especially the pileus. In contrast, red light slightly (non-significantly) inhibited pileus growth. When compared with red-light and dark treatments, blue-light treatment significantly upregulated gene expression involved in glycolysis/gluconeogenesis, the pentose phosphate pathway and the peroxisome in the pileus, but not in the gill or stipe. Most of the glycolysis and pentose phosphate pathway genes were upregulated in the pileus by blue light. When compared with dark treatment, red-light treatment downregulated the expression of many respiration metabolism genes in the pileus. These results revealed that blue light enhanced the activation of glycolysis and the pentose phosphate pathway, whereas red light weakened glycolysis and pentose phosphate pathway activation. The conclusion can be drawn that blue light improved P. ostreatus fruiting body (particularly, the pileus) growth rate via enhancement of glycolysis and the pentose phosphate pathway.
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http://dx.doi.org/10.1186/s13568-020-0951-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6969877PMC
January 2020

Word Frequency Is Associated With Cognitive Effort During Verbal Working Memory: A Functional Near Infrared Spectroscopy (fNIRS) Study.

Front Hum Neurosci 2019 13;13:433. Epub 2019 Dec 13.

School of Behavioral and Brain Sciences, The University of Texas at Dallas, Dallas, TX, United States.

Purpose: Psycholinguistic models traditionally view verbal working memory capacity as independent from linguistic features; connectionist models suggest otherwise. Moreover, lexical processing studies show high frequency words differ in cognitive effort from low frequency words, although these effects during concurrent processing of words in working memory are unknown. This novel study examines potential differences in cognitive effort, as measured by differences in HbO2 and Hb, for high frequency versus low frequency words during a working memory paradigm.

Methods: A total of 21 neurologically typical participants (age 18-23) completed an auditory, -back, working memory task comparing performance with high- as compared to low- frequency words. Hemodynamic changes in the prefrontal cortex were recorded with a continuous-wave functional near-infrared spectroscopy (fNIRS) device. Behavioral data (accuracy, reaction time) were recorded using E-prime.

Results: Differences in word frequency were evident at both behavioral and neurological levels. Participants were more accurate, albeit slower in identifying the target two back in a sequence for low- as compared to high-frequency words. Patterns of hemodynamic changes were also significantly different between HF and LF conditions.

Conclusion: The results from this study indicate that the behavioral and neurological signatures inherent in holding high- versus low-frequency words in working memory differs significantly. Specifically, the findings from this study indicated that words differing in frequency place different demands on cognitive processing load in memory updating tasks.
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http://dx.doi.org/10.3389/fnhum.2019.00433DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6923201PMC
December 2019

Near-infrared diffuse correlation spectroscopy tracks changes in oxygen delivery and utilization during exercise with and without isolated arterial compression.

Am J Physiol Regul Integr Comp Physiol 2020 01 20;318(1):R81-R88. Epub 2019 Nov 20.

Department of Kinesiology, University of Texas at Arlington, Arlington, Texas.

Near-infrared diffuse correlation spectroscopy (NIR-DCS) is an emerging technology for simultaneous measurement of skeletal muscle microvascular oxygen delivery and utilization during exercise. The extent to which NIR-DCS can track acute changes in oxygen delivery and utilization has not yet been fully established. To address this knowledge gap, 14 healthy men performed rhythmic handgrip exercise at 30% maximal voluntary contraction, with and without isolated brachial artery compression, designed to acutely reduce convective oxygen delivery to the exercising muscle. Radial artery blood flow (Duplex Ultrasound) and NIR-DCS derived variables [blood flow index (BFI), tissue oxygen saturation (), and metabolic rate of oxygen ()] were simultaneously measured. During exercise, both radial artery blood flow (+51.6 ± 20.3 mL/min) and DCS-derived BFI (+155.0 ± 82.2%) increased significantly ( < 0.001), whereas decreased -7.9 ± 6.2% ( = 0.002) from rest. Brachial artery compression during exercise caused a significant reduction in both radial artery blood flow (-32.0 ± 19.5 mL/min, = 0.001) and DCS-derived BFI (-57.3 ± 51.1%, = 0.01) and a further reduction of (-5.6 ± 3.8%, = 0.001) compared with exercise without compression. was not significantly reduced during arterial compression ( = 0.83) due to compensatory reductions in , driven by increases in deoxyhemoglobin/myoglobin (+7.1 ± 6.1 μM, = 0.01; an index of oxygen extraction). Together, these proof-of-concept data help to further validate NIR-DCS as an effective tool to assess the determinants of skeletal muscle oxygen consumption at the level of the microvasculature during exercise.
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http://dx.doi.org/10.1152/ajpregu.00212.2019DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6985795PMC
January 2020

Optimization of agro-residues as substrates for Pleurotus pulmonarius production.

AMB Express 2019 Nov 14;9(1):184. Epub 2019 Nov 14.

Engineering Research Center of Edible and Medicinal Fungi, Ministry of Education, Jilin Agricultural University, Changchun, 130118, China.

The "replacing wood by grass" project can partially resolve the conflict between mushroom production and balancing the ecosystem, while promoting agricultural economic sustainability. Pleurotus pulmonarius is an economically important edible and medicinal mushroom, which is traditionally produced using a substrate consisting of sawdust and cottonseed hulls, supplemented with wheat bran. A simplex lattice design was applied to systemically optimize the cultivation of P. pulmonarius using agro-residues as the main substrate to replace sawdust and cottonseed hulls. The effects of differing amounts of wheat straw, corn straw, and soybean straw on the variables of yield, mycelial growth rate, stipe length, pileus length, pileus width, and time to harvest were demonstrated. Results indicated that a mix of wheat straw, corn straw, and soybean straw may have significantly positive effects on each of these variables. The high yield comprehensive formula was then optimized to include 40.4% wheat straw, 20.3% corn straw, 18.3% soybean straw, combined with 20.0% wheat bran, and 1.0% light CaCO (C/N = 42.50). The biological efficiency was 15.2% greater than that of the control. Most encouraging was the indication that the high yield comprehensive formula may shorten the time to reach the reproductive stage by 6 days, compared with the control. Based on the results of this study, agro-residues may be used as a suitable substitution for sawdust and cottonseed hulls as the main cultivation substrates of P. pulmonarius. These results provide a theoretical basis for the "replacing wood by grass" project on edible mushroom cultivation.
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http://dx.doi.org/10.1186/s13568-019-0907-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6856248PMC
November 2019

Determinants of skeletal muscle oxygen consumption assessed by near-infrared diffuse correlation spectroscopy during incremental handgrip exercise.

J Appl Physiol (1985) 2019 09 18;127(3):698-706. Epub 2019 Jul 18.

Department of Kinesiology, University of Texas at Arlington, Arlington, Texas.

Near-infrared diffuse correlation spectroscopy (DCS) is a rapidly evolving optical imaging technique for the assessment of skeletal muscle O utilization (mVO). We compared DCS-derived determinants of mVO with conventional measures [blood flow by brachial artery Doppler ultrasound and venous O saturation ()] in eight volunteers at rest and during incremental handgrip exercise. Brachial artery blood flow and DCS-derived blood flow index (BFI) were linearly related (R = 0.57) and increased with each workload, whereas decreased from 65.3 ± 2.5% (rest) to 39.9 ± 3.0% (light exercise; < 0.01) with no change thereafter. In contrast, DCS-derived tissue O saturation decreased progressively with each incremental stage ( < 0.01), driven almost entirely by an initial steep rise in deoxyhemoglobin/myoglobin, followed by a linear increase thereafter. Whereas seemingly disparate at first glance, we believe these two approaches provide similar information. Indeed, by plotting the mean convective O delivery and diffusive O conductance, we show that the initial increase in mVO during the transition from rest to exercise was achieved by a greater increase in diffusive O conductance versus convective O delivery (10-fold vs. 4-fold increase, respectively), explaining the initial decline in . In contrast, the increase in mVO from light to heavy exercise was achieved by equal increases (1.8-fold) in convective O delivery and diffusive O conductance, explaining the plateau in . That DCS-derived BFI and deoxyhemoglobin/myoglobin (surrogate measure of O extraction) share the same general biphasic pattern suggests that both DCS and conventional approaches provide complementary information regarding the determinants of mVO. Near-infrared diffuse correlation spectroscopy (DCS) is an emerging optical imaging technique for quantifying skeletal muscle O delivery and utilization at the microvascular level. Here, we show that DCS provides complementary insight into the determinants of muscle O consumption across a wide range of exercise intensities, further establishing the utility of DCS.
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http://dx.doi.org/10.1152/japplphysiol.00273.2019DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6766713PMC
September 2019

Studies into the determinants of skeletal muscle oxygen consumption: novel insight from near-infrared diffuse correlation spectroscopy.

J Physiol 2019 06 29;597(11):2887-2901. Epub 2019 Apr 29.

Department of Kinesiology, University of Texas at Arlington, Arlington, TX, USA.

Key Points: Diffuse correlation spectroscopy (DCS) is emerging as a powerful tool to assess skeletal muscle perfusion. Near-infrared spectroscopy (NIRS) is an established technique for characterizing the transport and utilization of oxygen through the microcirculation. Here we compared a combined NIRS-DCS system with conventional measures of oxygen delivery and utilization during handgrip exercise. The data show good concurrent validity between convective oxygen delivery and DCS-derived blood flow index, as well as between oxygen extraction at the conduit and microvascular level. We then manipulated forearm arterial perfusion pressure by adjusting the position of the exercising arm relative to the position of the heart. The data show that microvascular perfusion can be uncoupled from convective oxygen delivery, and that tissue saturation seemingly compensates to maintain skeletal muscle oxygen consumption. Taken together, these data support a novel role for NIRS-DCS in understanding the determinants of muscle oxygen consumption at the microvascular level.

Abstract: Diffuse correlation spectroscopy (DCS) is emerging as a powerful tool to assess skeletal muscle perfusion. Combining DCS with near-infrared spectroscopy (NIRS) introduces exciting possibilities for understanding the determinants of muscle oxygen consumption; however, no investigation has directly compared NIRS-DCS to conventional measures of oxygen delivery and utilization in an exercising limb. To address this knowledge gap, nine healthy males performed rhythmic handgrip exercise with simultaneous measurements by NIRS-DCS, Doppler blood flow and venous oxygen content. The two approaches showed good concurrent validity, with directionally similar responses between: (a) Doppler-derived forearm blood flow and DCS-derived blood flow index (BFI), and (b) venous oxygen saturation and NIRS-derived tissue saturation. To explore the utility of combined NIRS-DCS across the physiological spectrum, we manipulated forearm arterial perfusion pressure by altering the arm position above or below the level of the heart. As expected, Doppler-derived skeletal muscle blood flow increased with exercise in both arm positions, but with markedly different magnitudes (below: +424.3 ± 41.4 ml/min, above: +306 ± 12.0 ml/min, P = 0.002). In contrast, DCS-derived microvascular BFI increased to a similar extent with exercise, regardless of arm position (P = 0.65). Importantly, however, the time to reach BFI steady state was markedly slower with the arm above the heart, supporting the experimental design. Notably, we observed faster tissue desaturation at the onset of exercise with the arm above the heart, resulting in similar muscle oxygen consumption profiles throughout exercise. Taken together, these data support a novel role for NIRS-DCS in understanding the determinants of skeletal muscle oxygen utilization non-invasively and throughout exercise.
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http://dx.doi.org/10.1113/JP277580DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8024923PMC
June 2019

A Pilot Study Identifying Brain-Targeting Adaptive Immunity in Pediatric Extracorporeal Membrane Oxygenation Patients With Acquired Brain Injury.

Crit Care Med 2019 03;47(3):e206-e213

Departments of Neurology and Neurotherapeutics, UT Southwestern Medical Center, Dallas, TX.

Objectives: Extracorporeal membrane oxygenation provides short-term cardiopulmonary life support, but is associated with peripheral innate inflammation, disruptions in cerebral autoregulation, and acquired brain injury. We tested the hypothesis that extracorporeal membrane oxygenation also induces CNS-directed adaptive immune responses which may exacerbate extracorporeal membrane oxygenation-associated brain injury.

Design: A single center prospective observational study.

Setting: Pediatric and cardiac ICUs at a single tertiary care, academic center.

Patients: Twenty pediatric extracorporeal membrane oxygenation patients (0-14 yr; 13 females, 7 males) and five nonextracorporeal membrane oxygenation Pediatric Logistic Organ Dysfunction score matched patients INTERVENTIONS:: None.

Measurements And Main Results: Venous blood samples were collected from the extracorporeal membrane oxygenation circuit at day 1 (10-23 hr), day 3, and day 7 of extracorporeal membrane oxygenation. Flow cytometry quantified circulating innate and adaptive immune cells, and CNS-directed autoreactivity was detected using an in vitro recall response assay. Disruption of cerebral autoregulation was determined using continuous bedside near-infrared spectroscopy and acquired brain injury confirmed by MRI. Extracorporeal membrane oxygenation patients with acquired brain injury (n = 9) presented with a 10-fold increase in interleukin-8 over extracorporeal membrane oxygenation patients without brain injury (p < 0.01). Furthermore, brain injury within extracorporeal membrane oxygenation patients potentiated an inflammatory phenotype in adaptive immune cells and selective autoreactivity to brain peptides in circulating B cell and cytotoxic T cell populations. Correlation analysis revealed a significant relationship between adaptive immune responses of extracorporeal membrane oxygenation patients with acquired brain injury and loss of cerebral autoregulation.

Conclusions: We show that pediatric extracorporeal membrane oxygenation patients with acquired brain injury exhibit an induction of pro-inflammatory cell signaling, a robust activation of adaptive immune cells, and CNS-targeting adaptive immune responses. As these patients experience developmental delays for years after extracorporeal membrane oxygenation, it is critical to identify and characterize adaptive immune cell mechanisms that target the developing CNS.
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http://dx.doi.org/10.1097/CCM.0000000000003621DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6377324PMC
March 2019

Enzymatic gene expression by Pleurotus tuoliensis (Bailinggu): differential regulation under low temperature induction conditions.

World J Microbiol Biotechnol 2018 Oct 19;34(11):160. Epub 2018 Oct 19.

Engineering Research Center of Chinese Ministry of Education for Edible and Medicinal Fungi, College of Agriculture, Jilin Agricultural University, Changchun, 130118, China.

Pleurotus tuoliensis is a valuable, rare and edible mushroom that is been commercially cultivated and is rapidly developing in China markets. Low temperatures are required to induces primordia initiation for the successful production of fruiting bodies (basidiomes) during commercial cultivation. In this work, we investigated the enzymatic activities and performed transcription profiling analysis of enzymatic genes under different low temperature conditions. The results suggest that the enzymatic activities and transcription levels decrease or increase significantly at 4 and 13 °C. Lacc10 and mnp6 seems to play a dominant role during nutrition growth. Furthermore, the expression of laccase and peroxidase genes was highly correlated to the detected extracellular enzymatic activity. Cold stress genes expression profiles were upregulated under 4 °C/13 °C (3 days), while only the Hsp70 gene was downregulated (at the stage of fruiting bodies production) at 13 °C (12 days). Our results showed that the transcriptional regulation of laccase and ligninolytic peroxidase genes plays an important role in the fruiting bodies of Bailinggu under low temperature induction (4 °C). Induction at low temperatures was a highly important cultivation condition in Bailinggu.
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http://dx.doi.org/10.1007/s11274-018-2487-7DOI Listing
October 2018

Identification of a putative polyketide synthase gene involved in usnic acid biosynthesis in the lichen Nephromopsis pallescens.

PLoS One 2018 18;13(7):e0199110. Epub 2018 Jul 18.

Engineering Research Center of Chinese Ministry of Education for Edible and Medicinal Fungi, Jilin Agricultural University, Changchun, China.

Usnic acid is a unique polyketide produced by lichens. To characterize usnic acid biosynthesis, the transcriptome of the usnic-acid-producing lichen-forming fungus Nephromopsis pallescens was sequenced using Illumina NextSeq technology. Seven complete non-reducing polyketide synthase genes and nine highly-reducing polyketide synthase genes were obtained through transcriptome analysis. Gene expression results obtained by qPCR and usnic acid detection with LCMS-IT-TOF showed that Nppks7 is probably involved in usnic acid biosynthesis in N. pallescens. Nppks7 is a non-reducing polyketide synthase with a MeT domain that also possesses beta-ketoacyl-ACP synthase, acyl transferase, product template, acyl carrier protein, C-methyltransferase, and Claisen cyclase domains. Phylogenetic analysis shows that Nppks7and other polyketide synthases from lichens form a unique monophyletic clade. Taken together, our data indicate that Nppks7 is a novel PKS in N. pallescens that is likely involved in usnic acid biosynthesis.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0199110PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6051580PMC
December 2018

An fNIRS-Based Feature Learning and Classification Framework to Distinguish Hemodynamic Patterns in Children Who Stutter.

IEEE Trans Neural Syst Rehabil Eng 2018 06;26(6):1254-1263

Stuttering is a communication disorder that affects approximately 1% of the population. Although 5-8% of preschool children begin to stutter, the majority will recover with or without intervention. There is a significant gap, however, in our understanding of why many children recover from stuttering while others persist and stutter throughout their lives. Detecting neurophysiological biomarkers of stuttering persistence is a critical objective of this paper. In this paper, we developed a novel supervised sparse feature learning approach to discover discriminative biomarkers from functional near infrared spectroscopy (fNIRS) brain imaging data recorded during a speech production experiment from 46 children in three groups: children who stutter ( ); children who do not stutter ( ); and children who recovered from stuttering ( ). We made an extensive feature analysis of the cerebral hemodynamics from fNIRS signals and selected a small number of important discriminative features using the proposed sparse feature learning framework. The selected features are capable of differentiating neural activation patterns between children who do and do not stutter with an accuracy of 87.5% based on a five-fold cross-validation procedure. The discovered set cerebral hemodynamics features are presented as a set of promising biomarkers to elucidate the underlying neurophysiology in children who have recovered or persisted in stuttering and to facilitate future data-driven diagnostics in these children.
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http://dx.doi.org/10.1109/TNSRE.2018.2829083DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6242270PMC
June 2018

Concurrent measurement of skeletal muscle blood flow during exercise with diffuse correlation spectroscopy and Doppler ultrasound.

Biomed Opt Express 2018 01 8;9(1):131-141. Epub 2017 Dec 8.

Department of Bioengineering, The University of Texas at Arlington, 500 UTA Blvd., Arlington, TX 76010, USA.

Noninvasive, direct measurement of local muscle blood flow in humans remains limited. Diffuse correlation spectroscopy (DCS) is an emerging technique to measure regional blood flow at the microvascular level. In order to better understand the strengths and limitations of this novel technique, we performed a validation study by comparing muscle blood flow changes measured with DCS and Doppler ultrasound during exercise. Nine subjects were measured (all males, 27.4 ± 2.9 years of age) for a rhythmic handgrip exercise at 20% and 50% of individual maximum voluntary contraction (MVC), followed by a post-exercise recovery. The results from DCS and Doppler ultrasound were highly correlated ( = 0.99 ± 0.02). DCS was more reliable and less susceptible to motion artifact.
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http://dx.doi.org/10.1364/BOE.9.000131DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5772569PMC
January 2018

Impairment of cerebral autoregulation in pediatric extracorporeal membrane oxygenation associated with neuroimaging abnormalities.

Neurophotonics 2017 Oct 19;4(4):041410. Epub 2017 Aug 19.

University of Texas Southwestern Medical Center, Department of Pediatrics, Dallas, Texas, United States.

Extracorporeal membrane oxygenation (ECMO) is a life-supporting therapy for critically ill patients with severe respiratory and/or cardiovascular failure. Cerebrovascular impairment can result in hemorrhagic and ischemic complications commonly seen in the patients supported on ECMO. We investigated the degree of cerebral autoregulation impairment during ECMO as well as whether it is predictive of neuroimaging abnormalities. Spontaneous fluctuations of mean arterial pressure (MAP) and cerebral tissue oxygen saturation ([Formula: see text]) were continuously measured during the ECMO run. The dynamic relationship between the MAP and [Formula: see text] fluctuations was assessed based on wavelet transform coherence (WTC). Neuroimaging was conducted during and/or after ECMO as standard of care, and the abnormalities were evaluated based on a scoring system that had been previously validated among ECMO patients. Of the 25 patients, 8 (32%) had normal neuroimaging, 7 (28%) had mild to moderate neuroimaging abnormalities, and the other 10 (40%) had severe neuroimaging abnormalities. The degrees of cerebral autoregulation impairment quantified based on WTC showed significant correlations with the neuroimaging scores ([Formula: see text]; [Formula: see text]). Evidence that cerebral autoregulation impairment during ECMO was related to the patients' neurological outcomes was provided.
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http://dx.doi.org/10.1117/1.NPh.4.4.041410DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5562949PMC
October 2017

Elevated cranial ultrasound resistive indices are associated with improved neurodevelopmental outcomes one year after pediatric cardiac surgery: A single center pilot study.

Heart Lung 2017 Jul - Aug;46(4):251-257. Epub 2017 May 13.

Department of Pediatrics, Division of Critical Care Medicine, University of Texas Southwestern Medical Center, Children's Health Children's Medical Center at Dallas, USA.

Objective: To determine if a non-invasive, repeatable test can be used to predict neurodevelopmental outcomes in patients with congenital heart disease.

Methods: This was a prospective study of pediatric patients less than two months of age undergoing congenital heart surgery at the Children's Health Children's Medical Center at Dallas. Multichannel near-infrared spectroscopy (NIRS) was utilized during the surgery, and ultrasound (US) resistive indices (RI) of the major cranial vessels were obtained prior to surgery, immediately post-operatively, and prior to discharge. Pearson's correlation, Fischer exact t test, and Fischer r to z transformation were used where appropriate.

Results: A total of 16 patients were enrolled. All had US data. Of the sixteen patients, two died prior to the neurodevelopmental testing, six did not return for the neurodevelopmental testing, and eight patients completed the neurodevelopmental testing. There were no significant correlations between the prior to surgery and prior to discharge US RI and neurodevelopmental outcomes. The immediate post-operative US RI demonstrated a strong positive correlation with standardized neurodevelopmental outcome measures. We were able to demonstrate qualitative differences using multichannel NIRS during surgery, but experienced significant technical difficulties implementing consistent monitoring.

Conclusions: A higher resistive index in the major cerebral blood vessels following cardiac surgery in the neonatal period is associated with improved neurological outcomes one year after surgery. Obtaining an ultrasound with resistive indices of the major cerebral vessels prior to and after surgery may yield information that is predictive of neurodevelopmental outcomes.
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http://dx.doi.org/10.1016/j.hrtlng.2017.04.009DOI Listing
August 2017

Novel Wavelet Real Time Analysis of Neurovascular Coupling in Neonatal Encephalopathy.

Sci Rep 2017 04 10;7:45958. Epub 2017 Apr 10.

Department of internal medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA.

Birth asphyxia constitutes a major global public health burden for millions of infants, despite hypothermia therapy. There is a critical need for real time surrogate markers of therapeutic success, to aid in patient selection and/or modification of interventions in neonatal encephalopathy (NE). This is a proof of concept study aiming to quantify neurovascular coupling (NVC) using wavelet analysis of the dynamic coherence between amplitude-integrated electroencephalography (aEEG) and near-infrared spectroscopy in NE. NVC coupling is assessed by a wavelet metric estimation of percent time of coherence between NIRS SO and aEEG for 78 hours after birth. An abnormal outcome was predefined by a Bayley III score <85 by 18-24 m. We observed high coherence, intact NVC, between the oscillations of SO and aEEG in the frequency range of 0.00025-0.001 Hz in the non-encephalopathic newborns. NVC coherence was significantly decreased in encephalopathic newborns who were cooled vs. non-encephalopathic controls (median IQR 3[2-9] vs.36 [33-39]; p < 0.01), and was significantly lower in those with abnormal 24 months outcomes relative to those with normal outcomes (median IQR 2[1-3] vs 28[19-26], p = 0.04). Wavelet coherence analysis of neurovascular coupling in NE may identify infants at risk for abnormal outcomes.
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http://dx.doi.org/10.1038/srep45958DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5385531PMC
April 2017

Up-regulation of cerebral cytochrome-c-oxidase and hemodynamics by transcranial infrared laser stimulation: A broadband near-infrared spectroscopy study.

J Cereb Blood Flow Metab 2017 Dec 9;37(12):3789-3802. Epub 2017 Feb 9.

1 Department of Bioengineering, University of Texas at Arlington, Arlington, TX, USA.

Transcranial infrared laser stimulation (TILS) is a noninvasive form of brain photobiomulation. Cytochrome-c-oxidase (CCO), the terminal enzyme in the mitochondrial electron transport chain, is hypothesized to be the primary intracellular photoacceptor. We hypothesized that TILS up-regulates cerebral CCO and causes hemodynamic changes. We delivered 1064-nm laser stimulation to the forehead of healthy participants ( n = 11), while broadband near-infrared spectroscopy was utilized to acquire light reflectance from the TILS-treated cortical region before, during, and after TILS. Placebo experiments were also performed for accurate comparison. Time course of spectroscopic readings were analyzed and fitted to the modified Beer-Lambert law. With respect to the placebo readings, we observed (1) significant increases in cerebral concentrations of oxidized CCO (Δ[CCO]; >0.08 µM; p < 0.01), oxygenated hemoglobin (Δ[HbO]; >0.8 µM; p < 0.01), and total hemoglobin (Δ[HbT]; >0.5 µM; p < 0.01) during and after TILS, and (2) linear interplays between Δ[CCO] versus Δ[HbO] and between Δ[CCO] versus Δ[HbT]. Ratios of Δ[CCO]/Δ[HbO] and Δ[CCO]/Δ[HbT] were introduced as TILS-induced metabolic-hemodynamic coupling indices to quantify the coupling strength between TILS-enhanced cerebral metabolism and blood oxygen supply. This study provides the first demonstration that TILS causes up-regulation of oxidized CCO in the human brain, and contributes important insight into the physiological mechanisms.
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http://dx.doi.org/10.1177/0271678X17691783DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5718323PMC
December 2017

Prefrontal hemodynamic mapping by functional near-infrared spectroscopy in response to thermal stimulations over three body sites.

Neurophotonics 2016 Oct 19;3(4):045008. Epub 2016 Dec 19.

University of Texas at Arlington , Department of Bioengineering, P.O. Box 19138, Arlington, Texas 76019, United States.

Functional near-infrared spectroscopy (fNIRS) was used to examine hemodynamic responses in the prefrontal cortex (PFC) during noxious thermal pain, induced by thermal stimulations over three different body sites over the right forearm, right temporomandibular joint, and left forearm. Functional NIRS measurements were obtained from three groups of healthy volunteers, one group for each body region. Each group was subjected to both low-pain stimulation (LPS) and high-pain stimulation (HPS) by a [Formula: see text] thermode of a temperature-controlled thermal stimulator over the respective three body sites. Our results showed that HPS given at three sites induced significant increases ([Formula: see text]) in oxy-hemoglobin concentration ([Formula: see text]) in the PFC with similar temporal patterns in relatively spread PFC areas. In contrast, LPS did not cause any significant [Formula: see text] in the PFC of any subject group. Our observed PFC activations induced by acute HPS were generally consistent with previous reports by fMRI studies. The study also found a peculiar global trend of postpain deactivation in the PFC, which is attributed to global vasoconstriction due to acute nocuous pain. Overall, these results indicate that hemodynamic activities in PFC exhibit consistent temporal and spatial patterns in response to acute thermal stimulation given across all three body sites.
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http://dx.doi.org/10.1117/1.NPh.3.4.045008DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5166717PMC
October 2016

Regional Cerebral Abnormalities Measured by Frequency-Domain Near-Infrared Spectroscopy in Pediatric Patients During Extracorporeal Membrane Oxygenation.

ASAIO J 2017 Sep/Oct;63(5):e52-e59

From the *Department of Bioengineering, University of Texas at Arlington, Arlington, Texas; †Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, Texas; and ‡Children's Health, Dallas, Texas.

Extracorporeal membrane oxygenation (ECMO) is a form of advanced cardiorespiratory support provided to critically ill patients with severe respiratory or cardiovascular failure. While children undergoing ECMO therapy have significant risk for neurological morbidity, currently there is a lack of reliable bedside tool to detect the neurologic events for patients on ECMO. This study assessed the feasibility of frequency-domain near-infrared spectroscopy (NIRS) for detection of intracranial complications during ECMO therapy. The frequency-domain NIRS device measured the absorption coefficient (µa) and reduced scattering coefficient (µs') at six cranial positions from seven pediatric patients (0-16 years) during ECMO support and five healthy controls (2-14 years). Regional abnormalities in both absorption and scattering were identified among ECMO patients. A main finding in this study is that the abnormalities in scattering appear to be associated with lower-than-normal µs' values in regional areas of the brain. Because light scattering originates from the intracellular structures (such as nuclei and mitochondria), a reduction in scattering primarily reflects loss or decreased density of the brain matter. The results from this study indicate a potential to use the frequency-domain NIRS as a safe and complementary technology for detection of intracranial complications during ECMO therapy.
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http://dx.doi.org/10.1097/MAT.0000000000000453DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6609454PMC
April 2018

Interplay between up-regulation of cytochrome-c-oxidase and hemoglobin oxygenation induced by near-infrared laser.

Sci Rep 2016 08 3;6:30540. Epub 2016 Aug 3.

Department of Bioengineering, the University of Texas at Arlington, 500 UTA Blvd, Arlington, TX 76010, USA.

Photobiomodulation, also known as low-level laser/light therapy (LLLT), refers to the use of red-to-near-infrared light to stimulate cellular functions for physiological or clinical benefits. The mechanism of LLLT is assumed to rely on photon absorption by cytochrome c oxidase (CCO), the terminal enzyme in the mitochondrial respiratory chain that catalyzes the reduction of oxygen for energy metabolism. In this study, we used broadband near-infrared spectroscopy (NIRS) to measure the LLLT-induced changes in CCO and hemoglobin concentrations in human forearms in vivo. Eleven healthy participants were administered with 1064-nm laser and placebo treatments on their right forearms. The spectroscopic data were analyzed and fitted with wavelength-dependent, modified Beer-Lambert Law. We found that LLLT induced significant increases of CCO concentration (Δ[CCO]) and oxygenated hemoglobin concentration (Δ[HbO]) on the treated site as the laser energy dose accumulated over time. A strong linear interplay between Δ[CCO] and Δ[HbO] was observed for the first time during LLLT, indicating a hemodynamic response of oxygen supply and blood volume closely coupled to the up-regulation of CCO induced by photobiomodulation. These results demonstrate the tremendous potential of broadband NIRS as a non-invasive, in vivo means to study mechanisms of photobiomodulation and perform treatment evaluations of LLLT.
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http://dx.doi.org/10.1038/srep30540DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4971496PMC
August 2016

Prefrontal responses to Stroop tasks in subjects with post-traumatic stress disorder assessed by functional near infrared spectroscopy.

Sci Rep 2016 07 25;6:30157. Epub 2016 Jul 25.

The University of Texas at Arlington, Department of Bioengineering, Arlington, TX 76019, USA.

Studies on posttraumatic stress disorder (PTSD) showing attentional deficits have implicated abnormal activities in the frontal lobe. In this study, we utilized multichannel functional near-infrared spectroscopy (fNIRS) to investigate selective attention-related hemodynamic activity in the prefrontal cortex among 15 combat-exposed war-zone veterans with PTSD and 13 age- and gender-matched healthy controls. While performing the incongruent Stroop task, healthy controls showed significant activations in the left lateral prefrontal cortex (LPFC) compared to baseline readings. This observation is consistent with previously reported results. In comparison, subjects with PTSD failed to activate left LPFC during the same Stroop task. Our observations may implicate that subjects with PTSD experienced difficulty in overcoming Stroop interference. We also observed significant negative correlation between task reaction times and hemodynamic responses from left LPFC during the incongruent Stroop task in the PTSD group. Regarding the methodology used in this study, we have learned that an appropriate design of Stroop paradigms is important for meeting an optimal cognitive load which can lead to better brain image contrasts in response to Stroop interference between healthy versus PTSD subjects. Overall, the feasibility of fNIRS for studying and mapping neural correlates of selective attention and interference in subjects with PTSD is reported.
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http://dx.doi.org/10.1038/srep30157DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4995363PMC
July 2016

Wavelet coherence analysis of dynamic cerebral autoregulation in neonatal hypoxic-ischemic encephalopathy.

Neuroimage Clin 2016 25;11:124-132. Epub 2016 Jan 25.

Department of Pediatrics, University of Texas Southwestern Medical Center, United States. Electronic address:

Cerebral autoregulation represents the physiological mechanisms that keep brain perfusion relatively constant in the face of changes in blood pressure and thus plays an essential role in normal brain function. This study assessed cerebral autoregulation in nine newborns with moderate-to-severe hypoxic-ischemic encephalopathy (HIE). These neonates received hypothermic therapy during the first 72 h of life while mean arterial pressure (MAP) and cerebral tissue oxygenation saturation (SctO2) were continuously recorded. Wavelet coherence analysis, which is a time-frequency domain approach, was used to characterize the dynamic relationship between spontaneous oscillations in MAP and SctO2. Wavelet-based metrics of phase, coherence and gain were derived for quantitative evaluation of cerebral autoregulation. We found cerebral autoregulation in neonates with HIE was time-scale-dependent in nature. Specifically, the spontaneous changes in MAP and SctO2 had in-phase coherence at time scales of less than 80 min (< 0.0002 Hz in frequency), whereas they showed anti-phase coherence at time scales of around 2.5 h (~ 0.0001 Hz in frequency). Both the in-phase and anti-phase coherence appeared to be related to worse clinical outcomes. These findings suggest the potential clinical use of wavelet coherence analysis to assess dynamic cerebral autoregulation in neonatal HIE during hypothermia.
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http://dx.doi.org/10.1016/j.nicl.2016.01.020DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4753811PMC
December 2016

Cerebral Hemodynamics in Asphyxiated Newborns Undergoing Hypothermia Therapy: Pilot Findings Using a Multiple-Time-Scale Analysis.

Pediatr Neurol 2016 Feb 27;55:30-6. Epub 2015 Nov 27.

Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas; Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital of Dallas, Dallas, Texas.

Background: Improved quantitative assessment of cerebral hemodynamics in newborns might enable us to optimize cerebral perfusion. Our objective was to develop an approach to assess cerebral hemodynamics across multiple time scales during the first 72 hours of life in newborns during hypothermia therapy.

Methods: Spontaneous oscillations in mean arterial pressure and regional cerebral tissue oxygen saturation were analyzed using a moving window correlation method with time scales ranging from 0.15 to 8 hours in this pilot methodology study. Abnormal neurodevelopmental outcome was defined by Bayley III scores and/or cerebral palsy by age 24 months using receiver operating curve.

Results: Multiple-time-scale correlations between the mean arterial pressure and regional cerebral tissue oxygen saturation oscillations were tested in 10 asphyxiated newborns undergoing hypothermia therapy. Large noninduced fluctuations in the blood pressure were observed during cooling in all five infants with abnormal outcomes. Notably, these infants had two distinct patterns of correlation: a positive in-phase correlation at the short time scales (15 minutes) and/or a negative antiphase correlations observed at long time scales (4 hours.). Both the in-phase (area under the curve 0.6, [95% confidence interval 0.2-0.95]) and antiphase correlations (area under the curve 0.75, [95% confidence interval 0.4-0.95]) appeared to be related to an abnormal outcome.

Conclusions: Our observations suggest that the time scale is an important factor that needs to be standardized in the assessment of neonatal cerebral hemodynamics.
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http://dx.doi.org/10.1016/j.pediatrneurol.2015.11.010DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4748172PMC
February 2016
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