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1.
J Neurosci ; 40(21): 4090-4102, 2020 05 20.
Article in English | MEDLINE | ID: mdl-32312887

ABSTRACT

Neurons can respond to decreased network activity with a homeostatic increase in the amplitudes of miniature EPSCs (mEPSCs). The prevailing view is that mEPSC amplitudes are uniformly multiplied by a single factor, termed "synaptic scaling." Deviations from purely multiplicative scaling have been attributed to biological differences, or to a distortion imposed by a detection threshold limit. Here, we demonstrate in neurons dissociated from cortices of male and female mice that the shift in mEPSC amplitudes observed in the experimental data cannot be reproduced by simulation of uniform multiplicative scaling, with or without the distortion caused by applying a detection threshold. Furthermore, we demonstrate explicitly that the scaling factor is not uniform but is close to 1 for small mEPSCs, and increases with increasing mEPSC amplitude across a substantial portion of the data. This pattern was also observed for previously published data from dissociated mouse hippocampal neurons and dissociated rat cortical neurons. The finding of "divergent scaling" shifts the current view of homeostatic plasticity as a process that alters all synapses on a neuron equally to one that must accommodate the differential effect observed for small versus large mEPSCs. Divergent scaling still accomplishes the essential homeostatic task of modifying synaptic strengths in the opposite direction of the activity change, but the consequences are greatest for those synapses which individually are more likely to bring a neuron to threshold.SIGNIFICANCE STATEMENT In homeostatic plasticity, the responses to chronic increases or decreases in network activity act in the opposite direction to restore normal activity levels. Homeostatic plasticity is likely to play a role in diseases associated with long-term changes in brain function, such as epilepsy and neuropsychiatric illnesses. One homeostatic response is the increase in synaptic strength following a chronic block of activity. Research is focused on finding a globally expressed signaling pathway, because it has been proposed that the plasticity is uniformly expressed across all synapses. Here, we show that the plasticity is not uniform. Our work suggests that homeostatic signaling molecules are likely to be differentially expressed across synapses.


Subject(s)
Cerebral Cortex/physiology , Excitatory Postsynaptic Potentials/physiology , Miniature Postsynaptic Potentials/physiology , Neuronal Plasticity/physiology , Neurons/physiology , Animals , Cells, Cultured , Mice , Patch-Clamp Techniques , Synapses/physiology , Synaptic Transmission/physiology
2.
Cereb Cortex ; 30(4): 2555-2572, 2020 04 14.
Article in English | MEDLINE | ID: mdl-31832634

ABSTRACT

Primary visual cortex (V1) is the locus of numerous forms of experience-dependent plasticity. Restricting visual stimulation to one eye at a time has revealed that many such forms of plasticity are eye-specific, indicating that synaptic modification occurs prior to binocular integration of thalamocortical inputs. A common feature of these forms of plasticity is the requirement for NMDA receptor (NMDAR) activation in V1. We therefore hypothesized that NMDARs in cortical layer 4 (L4), which receives the densest thalamocortical input, would be necessary for all forms of NMDAR-dependent and input-specific V1 plasticity. We tested this hypothesis in awake mice using a genetic approach to selectively delete NMDARs from L4 principal cells. We found, unexpectedly, that both stimulus-selective response potentiation and potentiation of open-eye responses following monocular deprivation (MD) persist in the absence of L4 NMDARs. In contrast, MD-driven depression of deprived-eye responses was impaired in mice lacking L4 NMDARs, as was L4 long-term depression in V1 slices. Our findings reveal a crucial requirement for L4 NMDARs in visual cortical synaptic depression, and a surprisingly negligible role for them in cortical response potentiation. These results demonstrate that NMDARs within distinct cellular subpopulations support different forms of experience-dependent plasticity.


Subject(s)
Evoked Potentials, Visual/physiology , Neuronal Plasticity/physiology , Photic Stimulation/methods , Receptors, N-Methyl-D-Aspartate/deficiency , Sensory Deprivation/physiology , Visual Cortex/physiology , Animals , Female , Male , Mice , Mice, Inbred C57BL , Mice, Knockout , Mice, Transgenic , Receptors, N-Methyl-D-Aspartate/genetics
3.
Proc Natl Acad Sci U S A ; 113(49): 14139-14144, 2016 12 06.
Article in English | MEDLINE | ID: mdl-27856748

ABSTRACT

A half-century of research on the consequences of monocular deprivation (MD) in animals has revealed a great deal about the pathophysiology of amblyopia. MD initiates synaptic changes in the visual cortex that reduce acuity and binocular vision by causing neurons to lose responsiveness to the deprived eye. However, much less is known about how deprivation-induced synaptic modifications can be reversed to restore normal visual function. One theoretically motivated hypothesis is that a period of inactivity can reduce the threshold for synaptic potentiation such that subsequent visual experience promotes synaptic strengthening and increased responsiveness in the visual cortex. Here we have reduced this idea to practice in two species. In young mice, we show that the otherwise stable loss of cortical responsiveness caused by MD is reversed when binocular visual experience follows temporary anesthetic inactivation of the retinas. In 3-mo-old kittens, we show that a severe impairment of visual acuity is also fully reversed by binocular experience following treatment and, further, that prolonged retinal inactivation alone can erase anatomical consequences of MD. We conclude that temporary retinal inactivation represents a highly efficacious means to promote recovery of function.


Subject(s)
Amblyopia/therapy , Evoked Potentials, Visual , Vision, Monocular , Animals , Cats , Female , Male , Mice , Models, Animal , Recovery of Function , Visual Acuity
4.
Development ; 142(1): 118-27, 2015 Jan 01.
Article in English | MEDLINE | ID: mdl-25480920

ABSTRACT

The pluripotent mammalian epiblast undergoes unusually fast cell proliferation. This rapid growth is expected to generate a high transcriptional demand, but the underlying mechanisms remain unknown. We show here that the chromatin remodeler Chd1 is required for transcriptional output and development of the mouse epiblast. Chd1(-/-) embryos exhibit proliferation defects and increased apoptosis, are smaller than controls by E5.5 and fail to grow, to become patterned or to gastrulate. Removal of p53 allows progression of Chd1(-/-) mutants only to E7.0-8.0, highlighting the crucial requirement for Chd1 during early post-implantation development. Chd1(-/-) embryonic stem cells (ESCs) have a self-renewal defect and a genome-wide reduction in transcriptional output at both known mRNAs and intergenic transcripts. These transcriptional defects were only uncovered when cell number-normalized approaches were used, and correlate with a lower engagement of RNAP II with transcribed genes in Chd1(-/-) ESCs. We further show that Chd1 directly binds to ribosomal DNA, and that both Chd1(-/-) epiblast cells in vivo and ESCs in vitro express significantly lower levels of ribosomal RNA. In agreement with these findings, mutant cells in vivo and in vitro exhibit smaller and more elongated nucleoli. Thus, the RNA output by both Pol I and II is reduced in Chd1(-/-) cells. Our data indicate that Chd1 promotes a globally elevated transcriptional output required to sustain the distinctly rapid growth of the mouse epiblast.


Subject(s)
DNA-Binding Proteins/metabolism , Germ Layers/growth & development , Germ Layers/metabolism , Transcription, Genetic , Animals , Apoptosis/genetics , Body Patterning/genetics , Cell Cycle/genetics , Crosses, Genetic , DNA, Ribosomal/genetics , DNA-Binding Proteins/deficiency , Embryo, Mammalian/cytology , Embryo, Mammalian/metabolism , Embryonic Development , Embryonic Stem Cells/cytology , Embryonic Stem Cells/metabolism , Female , Gastrulation/genetics , Gene Expression Regulation, Developmental , Male , Mice, Inbred C57BL , RNA Precursors/genetics
5.
Strahlenther Onkol ; 194(9): 843-854, 2018 09.
Article in English | MEDLINE | ID: mdl-29802435

ABSTRACT

PURPOSE: To investigate the quality of treatment plans of spinal radiosurgery derived from different planning and delivery systems. The comparisons include robotic delivery and intensity modulated arc therapy (IMAT) approaches. Multiple centers with equal systems were used to reduce a bias based on individual's planning abilities. The study used a series of three complex spine lesions to maximize the difference in plan quality among the various approaches. METHODS: Internationally recognized experts in the field of treatment planning and spinal radiosurgery from 12 centers with various treatment planning systems participated. For a complex spinal lesion, the results were compared against a previously published benchmark plan derived for CyberKnife radiosurgery (CKRS) using circular cones only. For two additional cases, one with multiple small lesions infiltrating three vertebrae and a single vertebra lesion treated with integrated boost, the results were compared against a benchmark plan generated using a best practice guideline for CKRS. All plans were rated based on a previously established ranking system. RESULTS: All 12 centers could reach equality (n = 4) or outperform (n = 8) the benchmark plan. For the multiple lesions and the single vertebra lesion plan only 5 and 3 of the 12 centers, respectively, reached equality or outperformed the best practice benchmark plan. However, the absolute differences in target and critical structure dosimetry were small and strongly planner-dependent rather than system-dependent. Overall, gantry-based IMAT with simple planning techniques (two coplanar arcs) produced faster treatments and significantly outperformed static gantry intensity modulated radiation therapy (IMRT) and multileaf collimator (MLC) or non-MLC CKRS treatment plan quality regardless of the system (mean rank out of 4 was 1.2 vs. 3.1, p = 0.002). CONCLUSIONS: High plan quality for complex spinal radiosurgery was achieved among all systems and all participating centers in this planning challenge. This study concludes that simple IMAT techniques can generate significantly better plan quality compared to previous established CKRS benchmarks.


Subject(s)
Benchmarking , Radiosurgery/methods , Radiotherapy Planning, Computer-Assisted/methods , Radiotherapy, Intensity-Modulated/methods , Spinal Neoplasms , Thoracic Vertebrae , Aged , Algorithms , Dose Fractionation, Radiation , Humans , Neoplasm Recurrence, Local/radiotherapy , Organs at Risk , Radiosurgery/instrumentation , Radiotherapy Dosage , Radiotherapy, Intensity-Modulated/instrumentation , Re-Irradiation , Robotic Surgical Procedures/instrumentation , Spinal Neoplasms/radiotherapy , Spinal Neoplasms/secondary , Thoracic Vertebrae/surgery
6.
Proc Natl Acad Sci U S A ; 112(14): E1734-43, 2015 Apr 07.
Article in English | MEDLINE | ID: mdl-25831528

ABSTRACT

Lineage specification during development involves reprogramming of transcriptional states, but little is known about how this is regulated in vivo. The chromatin remodeler chomodomain helicase DNA-binding protein 1 (Chd1) promotes an elevated transcriptional output in mouse embryonic stem cells. Here we report that endothelial-specific deletion of Chd1 leads to loss of definitive hematopoietic progenitors, anemia, and lethality by embryonic day (E)15.5. Mutant embryos contain normal numbers of E10.5 intraaortic hematopoietic clusters that express Runx1 and Kit, but these clusters undergo apoptosis and fail to mature into blood lineages in vivo and in vitro. Hematopoietic progenitors emerging from the aorta have an elevated transcriptional output relative to structural endothelium, and this elevation is Chd1-dependent. In contrast, hematopoietic-specific deletion of Chd1 using Vav-Cre has no apparent phenotype. Our results reveal a new paradigm of regulation of a developmental transition by elevation of global transcriptional output that is critical for hemogenesis and may play roles in other contexts.


Subject(s)
DNA-Binding Proteins/genetics , Gene Expression Regulation, Developmental , Hematopoietic Stem Cells/cytology , Transcription, Genetic , Animals , Aorta/metabolism , Apoptosis , Cell Differentiation , Chromatin/metabolism , Crosses, Genetic , DNA-Binding Proteins/physiology , Mice , Mice, Inbred C57BL , Mice, Knockout , Multigene Family , Mutation , Oligonucleotide Array Sequence Analysis , Phenotype
7.
J Acoust Soc Am ; 140(3): 2113, 2016 09.
Article in English | MEDLINE | ID: mdl-27914403

ABSTRACT

Attenuation of ultrasound waves traversing a medium is not only a result of absorption and scattering within a given tissue, but also of coherent scattering, including diffraction, refraction, and reflection of the acoustic wave at tissue boundaries. This leads to edge enhancement and other artifacts in most reconstruction algorithms, other than 3D wave migration with currently impractical, implementations. The presented approach accounts for energy loss at tissue boundaries by normalizing data based on variable sound speed, and potential density, of the medium using a k-space wave solver. Coupled with a priori knowledge of major sound speed distributions, physical attenuation values within broad ranges, and the assumption of homogeneity within segmented regions, an attenuation image representative of region bulk properties is constructed by solving a penalized weighted least squares optimization problem. This is in contradistinction to absorption or to conventional attenuation coefficient based on overall insertion loss with strong dependence on sound speed and impedance mismatches at tissue boundaries. This imaged property will be referred to as the bulk attenuation coefficient. The algorithm is demonstrated on an opposed array setup, with mean-squared-error improvements from 0.6269 to 0.0424 (dB/cm/MHz)2 for a cylindrical phantom, and 0.1622 to 0.0256 (dB/cm/MHz)2 for a windowed phantom.


Subject(s)
Acoustics , Algorithms , Phantoms, Imaging , Sound , Ultrasonic Waves
8.
J Tradit Chin Med ; 36(6): 701-5, 2016 12.
Article in English | MEDLINE | ID: mdl-29949329

ABSTRACT

OBJECTIVE: To investigate the therapeutic and preventive effects of Rorrico on influenza, especially influenza A viral infection, including swine flu (H1N1) in humans. METHODS: Eighty-nine subjects were recruited in Hong Kong and Macau, and divided into treatment group (TG) and prevention group (PG) based on their influenza A and swine flu symptoms. All subjects were prescribed Rorrico or placebo, and monitored by a Chinese medicine practitioner. Blood samples were collected before and after 7-day Rorrico or placebo treatment for laboratory investigations. RESULTS: After treatment, there were some full recoveries and obvious relief of onset symptoms in the TG. Blood test results showed that Rorrico produced (a) no adverse effects on subjects' renal and liver functions, muscle enzyme and hematological status, (b) no up-regulation of pro-inflammatory cytokines tumour necrosis factor-a and interleukin-18 in both TG and PG, (c) mild yet statistically significant elevation of plasma mannose-binding lectin (MBL) in PG. CONCLUSION: Rorrico has no up-regulating effect on the participants' immune response, or, equally likely, the immuno-modulatory effects of Rorrico do not non-specifically or unnecessarily promote inflammation when not required. It is possible that oral administration of Rorrico can promote hepatic synthesis of MBL in healthy PG subjects, thereby conferring increased protection against infection.


Subject(s)
Drugs, Chinese Herbal/administration & dosage , Influenza A Virus, H1N1 Subtype/drug effects , Influenza, Human/drug therapy , Animals , Cytokines/genetics , Cytokines/immunology , Humans , Influenza A Virus, H1N1 Subtype/physiology , Influenza, Human/genetics , Influenza, Human/immunology , Influenza, Human/virology , Swine , Swine Diseases/virology , Tumor Necrosis Factor-alpha/genetics , Tumor Necrosis Factor-alpha/immunology
9.
J Acoust Soc Am ; 137(2): 585-97, 2015 Feb.
Article in English | MEDLINE | ID: mdl-25697993

ABSTRACT

Echo decorrelation imaging, a method for mapping ablation-induced ultrasound echo changes, is analyzed. Local echo decorrelation is shown to approximate the decoherence spectrum of tissue reflectivity. Effects of the ultrasound measurement system, echo signal windowing, electronic noise, and tissue motion on echo decorrelation images are determined theoretically, leading to a method for reduction of motion and noise artifacts. Theoretical analysis is validated by simulations and experiments. Simulated decoherence of the scattering medium was recovered with root-mean-square error less than 10% with accuracy dependent on the correlation window size. Motion-induced decorrelation measured in an ex vivo pubovisceral muscle model showed similar trends to theoretical motion-induced decorrelation for a 2.1 MHz curvilinear array with decorrelation approaching unity for 3-4 mm elevational displacement or 1-1.6 mm range displacement. For in vivo imaging of porcine liver by a 7 MHz linear array, theoretical decorrelation computed using image-based motion estimates correlated significantly with measured decorrelation (r = 0.931, N = 10). Echo decorrelation artifacts incurred during in vivo radiofrequency ablation in the same porcine liver were effectively compensated based on the theoretical echo decorrelation model and measured pre-treatment decorrelation. These results demonstrate the potential of echo decorrelation imaging for quantification of heat-induced changes to the scattering tissue medium during thermal ablation.


Subject(s)
Ablation Techniques , Artifacts , Image Interpretation, Computer-Assisted/methods , Muscle, Skeletal/diagnostic imaging , Muscle, Skeletal/surgery , Ultrasonics/methods , Animals , Cattle , Computer Simulation , Humans , Models, Animal , Models, Theoretical , Motion , Reproducibility of Results , Scattering, Radiation , Ultrasonography
10.
Elife ; 122024 Jun 28.
Article in English | MEDLINE | ID: mdl-38941139

ABSTRACT

Homeostatic plasticity represents a set of mechanisms that are thought to recover some aspect of neural function. One such mechanism called AMPAergic scaling was thought to be a likely candidate to homeostatically control spiking activity. However, recent findings have forced us to reconsider this idea as several studies suggest AMPAergic scaling is not directly triggered by changes in spiking. Moreover, studies examining homeostatic perturbations in vivo have suggested that GABAergic synapses may be more critical in terms of spiking homeostasis. Here, we show results that GABAergic scaling can act to homeostatically control spiking levels. We found that perturbations which increased or decreased spiking in cortical cultures triggered multiplicative GABAergic upscaling and downscaling, respectively. In contrast, we found that changes in AMPA receptor (AMPAR) or GABAR transmission only influence GABAergic scaling through their indirect effect on spiking. We propose that GABAergic scaling represents a stronger candidate for spike rate homeostat than AMPAergic scaling.


Subject(s)
Action Potentials , Receptors, AMPA , Receptors, AMPA/metabolism , Animals , Action Potentials/physiology , Synapses/physiology , Synapses/metabolism , Neuronal Plasticity/physiology , GABAergic Neurons/physiology , GABAergic Neurons/metabolism , Synaptic Transmission/physiology , Cells, Cultured , gamma-Aminobutyric Acid/metabolism , Homeostasis
11.
Elife ; 122024 Feb 20.
Article in English | MEDLINE | ID: mdl-38376907

ABSTRACT

Basal forebrain cholinergic neurons modulate how organisms process and respond to environmental stimuli through impacts on arousal, attention, and memory. It is unknown, however, whether basal forebrain cholinergic neurons are directly involved in conditioned behavior, independent of secondary roles in the processing of external stimuli. Using fluorescent imaging, we found that cholinergic neurons are active during behavioral responding for a reward - even prior to reward delivery and in the absence of discrete stimuli. Photostimulation of basal forebrain cholinergic neurons, or their terminals in the basolateral amygdala (BLA), selectively promoted conditioned responding (licking), but not unconditioned behavior nor innate motor outputs. In vivo electrophysiological recordings during cholinergic photostimulation revealed reward-contingency-dependent suppression of BLA neural activity, but not prefrontal cortex. Finally, ex vivo experiments demonstrated that photostimulation of cholinergic terminals suppressed BLA projection neuron activity via monosynaptic muscarinic receptor signaling, while also facilitating firing in BLA GABAergic interneurons. Taken together, we show that the neural and behavioral effects of basal forebrain cholinergic activation are modulated by reward contingency in a target-specific manner.


Subject(s)
Amygdala , Basolateral Nuclear Complex , Cholinergic Neurons , Interneurons , Reward
12.
J Ultrasound Med ; 32(1): 93-104, 2013 Jan.
Article in English | MEDLINE | ID: mdl-23269714

ABSTRACT

OBJECTIVES: The purpose of this study was to retrospectively evaluate the effect of 3-dimensional automated ultrasound (3D-AUS) as an adjunct to digital breast tomosynthesis (DBT) on radiologists' performance and confidence in discriminating malignant and benign breast masses. METHODS: Two-view DBT (craniocaudal and mediolateral oblique or lateral) and single-view 3D-AUS images were acquired from 51 patients with subsequently biopsy-proven masses (13 malignant and 38 benign). Six experienced radiologists rated, on a 13-point scale, the likelihood of malignancy of an identified mass, first by reading the DBT images alone, followed immediately by reading the DBT images with automatically coregistered 3D-AUS images. The diagnostic performance of each method was measured using receiver operating characteristic (ROC) curve analysis and changes in sensitivity and specificity with the McNemar test. After each reading, radiologists took a survey to rate their confidence level in using DBT alone versus combined DBT/3D-AUS as potential screening modalities. RESULTS: The 6 radiologists had an average area under the ROC curve of 0.92 for both modalities (range, 0.89-0.97 for DBT and 0.90-0.94 for DBT/3D-AUS). With a Breast Imaging Reporting and Data System rating of 4 as the threshold for biopsy recommendation, the average sensitivity of the radiologists increased from 96% to 100% (P > .08) with 3D-AUS, whereas the specificity decreased from 33% to 25% (P > .28). Survey responses indicated increased confidence in potentially using DBT for screening when 3D-AUS was added (P < .05 for each reader). CONCLUSIONS: In this initial reader study, no significant difference in ROC performance was found with the addition of 3D-AUS to DBT. However, a trend to improved discrimination of malignancy was observed when adding 3D-AUS. Radiologists' confidence also improved with DBT/3DAUS compared to DBT alone.


Subject(s)
Breast Neoplasms/diagnostic imaging , Imaging, Three-Dimensional , Ultrasonography, Mammary/methods , Adult , Aged , Biopsy , Female , Humans , Middle Aged , Phantoms, Imaging , Pilot Projects , ROC Curve , Radiographic Image Enhancement/methods , Retrospective Studies , Sensitivity and Specificity , Software
13.
Front Neurosci ; 17: 1167007, 2023.
Article in English | MEDLINE | ID: mdl-37409104

ABSTRACT

Introduction: Deprivation of normal vision early in postnatal development elicits modifications of neural circuitry within the primary visual pathway that can cause a severe and intractable vision impairment (amblyopia). In cats, amblyopia is often modeled with monocular deprivation (MD), a procedure that involves temporarily closing the lids of one eye. Following long-term MD, brief inactivation of the dominant eye's retina can promote recovery from the anatomical and physiological effects of MD. In consideration of retinal inactivation as a viable treatment for amblyopia it is imperative to compare its efficacy against conventional therapy, as well as assess the safety of its administration. Methods: In the current study we compared the respective efficacies of retinal inactivation and occlusion of the dominant eye (reverse occlusion) to elicit physiological recovery from a prior long-term MD in cats. Because deprivation of form vision has been associated with development of myopia, we also examined whether ocular axial length or refractive error were altered by a period of retinal inactivation. Results: The results of this study demonstrate that after a period of MD, inactivation of the dominant eye for up to 10 days elicited significant recovery of visually-evoked potentials that was superior to the recovery measured after a comparable duration of reverse occlusion. After monocular retinal inactivation, measurements of ocular axial length and refractive error were not significantly altered from their pre-inactivation values. The rate of body weight gain also was not changed during the period of inactivation, indicating that general well-being was not affected. Discussion: These results provide evidence that inactivation of the dominant eye after a period of amblyogenic rearing promotes better recovery than eye occlusion, and this recovery was achieved without development of form-deprivation myopia.

14.
Biomedicines ; 11(3)2023 Mar 11.
Article in English | MEDLINE | ID: mdl-36979841

ABSTRACT

Preeclampsia (PE) occurs in women pregnant for more than 20 weeks with de novo hypertension and proteinuria, and is a devastating disease in maternal-fetal medicine. Cytokine tumor necrosis factor (TNF)-α may play a key role in the pathogenesis of PE. We conducted this study to investigate the regulatory regions of the TNF genes, by investigating two promoter polymorphisms, TNFA-308G/A (rs1800629) and -238G/A (rs361525), known to influence TNF expression, and their relationship to PE. An observational, monocentric, case-control study was conducted. We retrospectively collected 74 cases of severe PE and 119 pregnant women without PE as control. Polymerase chain reaction (PCR) was carried out for allele analysis. Higher A allele in women with PE was found in rs1800629 but not rs361525. In this study, we first found that polymorphism at the position -308, but not -238, in the promoter region of the TNF-α gene can contribute to severe PE in Taiwanese Han populations. The results of our study are totally different to previous Iranian studies, but have some similarity to a previous UK study. Further studies are required to confirm the roles of rs1800629 and rs361525 in PE with circulating TNF-α in PE.

15.
Opt Express ; 20(19): 21223-34, 2012 Sep 10.
Article in English | MEDLINE | ID: mdl-23037246

ABSTRACT

A 25 Gbits/s error-free on-off-keying (OOK) wireless link between an ultra high-speed W-band photonic transmitter-mixer (PTM) and a fast W-band envelope detector is demonstrated. At the transmission end, the high-speed PTM is developed with an active near-ballistic uni-traveling carrier photodiode (NBUTC-PD) integrated with broadband front-end circuitry via the flip-chip bonding technique. Compared to our previous work, the wireless data rate is significantly increased through the improvement on the bandwidth of the front-end circuitry together with the reduction of the intermediate-frequency (IF) driving voltage of the active NBUTC-PD. The demonstrated PTM has a record-wide IF modulation (DC-25 GHz) and optical-to-electrical fractional bandwidths (68-128 GHz, ~67%). At the receiver end, the demodulation is realized with an ultra-fast W-band envelope detector built with a zero-bias Schottky barrier diode with a record wide video bandwidth (37 GHz) and excellent sensitivity. The demonstrated PTM is expected to find applications in multi-gigabit short-range wireless communication.

16.
J Clin Ultrasound ; 39(1): 21-6, 2011 Jan.
Article in English | MEDLINE | ID: mdl-20949572

ABSTRACT

PURPOSE: To assess the value of fetal soft tissue volume (STV) of the upper arm in predicting small-for-gestational-age (SGA) fetuses using three-dimensional (3D) ultrasound (US). METHODS: We used 3D US to test the accuracy of fetal STV of the upper arm measurement in predicting SGA in a prospective cross-sectional study. RESULTS: Fetal STV of the upper arm assessed by 3D US can differentiate SGA fetuses from appropriate-for-gestational-age (AGA) fetuses. Using the 5th percentile as the cutoff, the sensitivity of fetal upper arm STV in predicting SGA fetuses was 84.1%, specificity, 93.4%, positive predictive value, 71.1%, negative predictive value, 96.8%, and overall accuracy, 91.9%. In addition, the diagnostic accuracy of fetal arm STV was better than that of the biparietal diameter, abdominal circumference, and femur length. CONCLUSION: Fetal STV of upper arm assessment by 3D US is a novel method to predict SGA fetuses.


Subject(s)
Arm/diagnostic imaging , Arm/embryology , Fetal Growth Retardation/diagnostic imaging , Ultrasonography, Prenatal/methods , Cross-Sectional Studies , Female , Humans , Imaging, Three-Dimensional/methods , Predictive Value of Tests , Pregnancy , Prospective Studies , ROC Curve , Reproducibility of Results , Sensitivity and Specificity
17.
Elife ; 102021 08 31.
Article in English | MEDLINE | ID: mdl-34464258

ABSTRACT

Monocular deprivation early in development causes amblyopia, a severe visual impairment. Prognosis is poor if therapy is initiated after an early critical period. However, clinical observations have shown that recovery from amblyopia can occur later in life when the non-deprived (fellow) eye is removed. The traditional interpretation of this finding is that vision is improved simply by the elimination of interocular suppression in primary visual cortex, revealing responses to previously subthreshold input. However, an alternative explanation is that silencing activity in the fellow eye establishes conditions in visual cortex that enable the weak connections from the amblyopic eye to gain strength, in which case the recovery would persist even if vision is restored in the fellow eye. Consistent with this idea, we show here in cats and mice that temporary inactivation of the fellow eye is sufficient to promote a full and enduring recovery from amblyopia at ages when conventional treatments fail. Thus, connections serving the amblyopic eye are capable of substantial plasticity beyond the critical period, and this potential is unleashed by reversibly silencing the fellow eye.


Subject(s)
Amblyopia/veterinary , Vision, Binocular/physiology , Animals , Cats , Female , Male , Mice , Mice, Inbred C57BL , Sensory Deprivation , Visual Acuity
18.
BMC Med Genomics ; 14(Suppl 3): 212, 2021 11 17.
Article in English | MEDLINE | ID: mdl-34789231

ABSTRACT

BACKGROUND: Skeletal dysplasia (SD) is one of the most common inherited neonatal disorders worldwide, where the recurrent pathogenic mutations in the FGFR2, FGFR3, COL1A1, COL1A2 and COL2A1 genes are frequently reported in both non-lethal and lethal SD. The traditional prenatal diagnosis of SD using ultrasonography suffers from lower accuracy and performed at latter gestational stage. Therefore, it remains in desperate need of precise and accurate prenatal diagnosis of SD in early pregnancy. With the advancements of next-generation sequencing (NGS) technology and bioinformatics analysis, it is feasible to develop a NGS-based assay to detect genetic defects in association with SD in the early pregnancy. METHODS: An ampliseq-based targeted sequencing panel was designed to cover 87 recurrent hotspots reported in 11 common dominant SD and run on both Ion Proton and NextSeq550 instruments. Thirty-six cell-free and 23 genomic DNAs were used for assay developed. Spike-in DNA prepared from standard sample harboring known mutation and normal sample were also employed to validate the established SD workflow. Overall performances of coverage, uniformity, and on-target rate, and the detecting limitations on percentage of fetal fraction and read depth were evaluated. RESULTS: The established targeted-seq workflow enables a single-tube multiplex PCR for library construction and shows high amplification efficiency and robust reproducibility on both Ion Proton and NextSeq550 platforms. The workflow reaches 100% coverage and both uniformity and on-target rate are > 96%, indicating a high quality assay. Using spike-in DNA with different percentage of known FGFR3 mutation (c.1138 G > A), the targeted-seq workflow demonstrated the ability to detect low-frequency variant of 2.5% accurately. Finally, we obtained 100% sensitivity and 100% specificity in detecting target mutations using established SD panel. CONCLUSIONS: An expanded panel for rapid and cost-effective genetic detection of SD has been developed. The established targeted-seq workflow shows high accuracy to detect both germline and low-frequency variants. In addition, the workflow is flexible to be conducted in the majority of the NGS instruments and ready for routine clinical application. Taken together, we believe the established panel provides a promising diagnostic or therapeutic strategy for prenatal genetic testing of SD in routine clinical practice.


Subject(s)
Genetic Testing , High-Throughput Nucleotide Sequencing , Female , Humans , Mutation , Pregnancy , Prenatal Diagnosis , Reproducibility of Results , Sequence Analysis, DNA
19.
Int J Nanomedicine ; 16: 8103-8115, 2021.
Article in English | MEDLINE | ID: mdl-34992362

ABSTRACT

INTRODUCTION: Although the preparation of lipid nanoparticles (LNPs) achieves great success, their retention of highly hydrophobic drugs is still problematic. METHODS: Herein, we report a novel strategy for efficiently loading hydrophobic drugs to LNPs for stroke therapy. Oleoylethanolamide (OEA), an endogenous highly hydrophobic molecule with outstanding neuroprotective effect, was successfully loaded to OEA-SPC&DSPE-PEG lipid nanoparticles (OSDP LNPs) with a drug loading of 15.9 ± 1.2 wt%. Efficient retention in OSDP LNPs greatly improved the pharmaceutical property and enhanced the neuroprotective effect of OEA. RESULTS: Through the data of positron emission tomography (PET) and TTC-stained brain slices, it could be clearly visualized that the acute ischemic brain tissues were preserved as penumbral tissues and bounced back with reperfusion. The in vivo experiments stated that OSDP LNPs could significantly improve the survival rate, the behavioral score, the cerebral infarct volume, the edema degree, the spatial learning and memory ability of the MCAO (middle cerebral artery occlusion) rats. DISCUSSION: These results suggest that the OSDP LNPs have a great chance to develop hydrophobic OEA into a potential anti-stroke formulation.


Subject(s)
Nanoparticles , Stroke , Animals , Endocannabinoids , Liposomes , Oleic Acids , Rats , Stroke/drug therapy
20.
Crit Care Med ; 38(10): 2043-51, 2010 Oct.
Article in English | MEDLINE | ID: mdl-20657272

ABSTRACT

OBJECTIVE: To ascertain whether Premarin improves spinal cord injury outcomes in male rats by stimulating both angiogenesis and neurogenesis. DESIGN: Chi Mei Medical Center research laboratory. SUBJECTS: Male Sprague-Dawley rats 240-258 g. INTERVENTIONS: Anesthetized rats, after the onset of spinal cord injury, were divided into two groups and given the vehicle solution (1 mL/kg of body weight) or Premarin (1 mg/kg of body weight). Saline or Premarin solutions were administered intravenously and immediately after spinal cord injury. MEASUREMENTS AND MAIN RESULTS: Premarin (an estrogen sulfate) causes attenuation of spinal cord injury-induced spinal cord infarction and hind limb locomotor dysfunction. Spinal cord injury-induced apoptosis as well as activated inflammation was also significantly Premarin-reduced. In injured spinal cord, angiogenesis, neurogenesis, and production of an antiinflammatory cytokine were all Premarin therapy-promoted. CONCLUSIONS: Our results indicate that Premarin therapy may protect against spinal cord apoptosis after spinal cord injury through mechanisms stimulating both angiogenesis and neurogenesis in male rats.


Subject(s)
Estrogens, Conjugated (USP)/therapeutic use , Estrogens/therapeutic use , Neovascularization, Physiologic/drug effects , Neurogenesis/drug effects , Spinal Cord Injuries/drug therapy , Animals , Apoptosis/drug effects , DNA Nucleotidylexotransferase/drug effects , Inflammation/drug therapy , Interleukin-10/blood , Male , Rats , Rats, Sprague-Dawley , Spinal Cord Injuries/physiopathology , Tumor Necrosis Factor-alpha/blood
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