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1.
J Biophotonics ; 13(2): e201960109, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31867878

RESUMO

Spontaneous Raman micro-spectroscopy has been demonstrated great potential in delineating tumor margins; however, it is limited by slow acquisition speed. We describe a superpixel acquisition approach that can expedite acquisition between ~×100 and ×10 000, as compared to point-by-point scanning by trading off spatial resolution. We present the first demonstration of superpixel acquisition on rapid discrimination of basal cell carcinoma tumor from eight patients undergoing Mohs micrographic surgery. Results have been demonstrated high discriminant power for tumor vs normal skin based on the biochemical differences between nucleus, collagen, keratin and ceramide. We further perform raster-scanned superpixel Raman imaging on positive and negative margin samples. Our results indicate superpixel acquisition can facilitate the use of Raman microspectroscopy as a rapid and specific tool for tumor margin assessment.

2.
Cancers (Basel) ; 11(12)2019 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-31805710

RESUMO

Advanced prostate cancer is a very heterogeneous disease reflecting in diverse regulations of oncogenic signaling pathways. Aberrant spatial dynamics of epidermal growth factor receptor (EGFR) promote their dimerization and clustering, leading to constitutive activation in oncogenesis. The EphB2 and Src signaling pathways are associated with the reorganization of the cytoskeleton leading to malignancy, but their roles in regulating EGFR dynamics and activation are scarcely reported. Using single-particle tracking techniques, we found that highly phosphorylated EGFR in the advanced prostate cancer cell line, PC3, was associated with higher EGFR diffusivity, as compared with LNCaP and less aggressive DU145. The increased EGFR activation and biophysical dynamics were consistent with high proliferation, migration, and invasion. After performing single-cell RNA-seq on prostate cancer cell lines and circulating tumor cells from patients, we identified that upregulated gene expression in the EphB2 and Src pathways are associated with advanced malignancy. After dasatinib treatment or siRNA knockdowns of EphB2 or Src, the PC3 cells exhibited significantly lower EGFR dynamics, cell motility, and invasion. Partial inhibitory effects were also found in DU145 cells. The upregulation of parts of the EphB2 and Src pathways also predicts poor prognosis in the prostate cancer patient cohort of The Cancer Genome Atlas. Our results provide evidence that overexpression of the EphB2 and Src signaling pathways regulate EGFR dynamics and cellular aggressiveness in some advanced prostate cancer cells.

3.
Opt Lett ; 44(20): 5017-5020, 2019 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-31613252

RESUMO

Conventional, degenerate multiphoton microscopy (D-MPM) requires the use of a high-numerical-aperture (NA) objective. Nondegenerate MPM (ND-MPM) imposes the additional demand for precise spatiotemporal overlap of two distinct excitation sources. We demonstrate that the axial focal shift introduced by refractive objective chromatic aberration hinders the spatial requirement of ND-MPM, whereas the use of a reflective objective overcomes this challenge and allows for improved ND excitation efficiency in spite of a lower NA. Moreover, we demonstrate that reflective objective focusing eliminates the axial misregistration of volumetric stacks in traditional D-MPM experiments when multiple excitation wavelengths are used.

4.
J Neurosci ; 39(43): 8471-8483, 2019 Oct 23.
Artigo em Inglês | MEDLINE | ID: mdl-31511430

RESUMO

After subtotal infarcts of primary motor cortex (M1), motor rehabilitative training (RT) promotes improvements in paretic forelimb function that have been linked with its promotion of structural and functional reorganization of peri-infarct cortex, but how the reorganization unfolds is scantly understood. Cortical infarcts also instigate a prolonged period of dendritic spine turnover in peri-infarct cortex. Here we investigated the possibility that synaptic structural responses to RT in peri-infarct cortex reflect, in part, interactions with ischemia-instigated spine turnover. This was tested after artery-targeted photothrombotic M1 infarcts or Sham procedures in adult (4 months) C57BL/6 male and female GFP-M line (n = 24) and male yellow fluorescent protein-H line (n = 5) mice undergoing RT in skilled reaching or no-training control procedures. Regardless of training condition, spine turnover was increased out to 5 weeks postinfarct relative to Sham, as was the persistence of new spines formed within a week postinfarct. However, compared with no-training controls, new spines formed during postinfarct weeks 2-4 in mice undergoing RT persisted in much greater proportions to later time points, by a magnitude that predicted behavioral improvements in the RT group. These results indicate that RT interacts with ischemia-instigated spine turnover to promote preferential stabilization of newly formed spines, which is likely to yield a new population of mature synapses in peri-infarct cortex that could contribute to cortical functional reorganization and behavioral improvement. The findings newly implicate ischemia-instigated spine turnover as a mediator of cortical synaptic structural responses to RT and newly establish the experience dependency of new spine fates in the postischemic turnover context.SIGNIFICANCE STATEMENT Motor rehabilitation, the main treatment for motor impairments after stroke, is far from sufficient to normalize function. A better understanding of neural substrates of rehabilitation-induced behavioral improvements could be useful for understanding how to optimize it. Here, we investigated the nature and time course of synaptic responses to motor rehabilitative training in vivo Focal ischemia instigated a period of synapse turnover in peri-infarct motor cortex of mice. Rehabilitative training increased the stability of new synapses formed during the initial weeks after the infarct, the magnitude of which was correlated with improvements in skilled motor performance. Therefore, the maintenance of new synapses formed after ischemia could represent a structural mechanism of rehabilitative training efficacy.

5.
Sci Rep ; 9(1): 3395, 2019 Mar 04.
Artigo em Inglês | MEDLINE | ID: mdl-30833579

RESUMO

Derailed transmembrane receptor trafficking could be a hallmark of tumorigenesis and increased tumor invasiveness, but receptor dynamics have not been used to differentiate metastatic cancer cells from less invasive ones. Using single-particle tracking techniques, we  developed a phenotyping asssay named Transmembrane Receptor Dynamics (TReD), studied the dynamics of epidermal growth factor receptor (EGFR) in seven breast epithelial cell lines and developed a phenotyping assay named Transmembrane Receptor Dynamics (TReD). Here we show a clear evidence that increased EGFR diffusivity and enlarged EGFR confinement size in the plasma membrane (PM) are correlated with the enhanced metastatic potential in these cell lines. By comparing the TReD results with the gene expression profiles, we found a clear negative correlation between the EGFR diffusivities and the breast cancer luminal differentiation scores (r = -0.75). Upon the induction of epithelial-mesenchymal transition (EMT), EGFR diffusivity significantly increased for the non-tumorigenic MCF10A (99%) and the non-invasive MCF7 (56%) cells, but not for the highly metastatic MDA-MB-231 cell. We believe that the reorganization of actin filaments during EMT modified the PM structures, causing the receptor dynamics to change. TReD can thus serve as a new biophysical marker to probe the metastatic potential of cancer cells and even to monitor the transition of metastasis.

6.
Sci Rep ; 9(1): 2323, 2019 Feb 20.
Artigo em Inglês | MEDLINE | ID: mdl-30787398

RESUMO

The photothrombotic stroke model generates localized and reproducible ischemic infarcts that are useful for studying recovery mechanisms, but its failure to produce a substantial ischemic penumbra weakens its resemblance to human stroke. We examined whether a modification of this approach, confining photodamage to arteries on the cortical surface (artery-targeted photothrombosis), could better reproduce aspects of the penumbra. Following artery-targeted or traditional photothrombosis to the motor cortex of mice, post-ischemic cerebral blood flow was measured using multi-exposure speckle imaging at 6, 48, and 120 h post-occlusion. Artery-targeted photothrombosis produced a more graded penumbra at 48 and 120 h. The density of isolectin B4+ vessels in peri-infarct cortex was similarly increased after both types of infarcts compared to sham at 2 weeks. These results indicate that both models instigated post-ischemic vascular structural changes. Finally, we determined whether the strength of the traditional photothrombotic approach for modeling upper-extremity motor impairments extends to the artery-targeted approach. In adult mice that were proficient in a skilled reaching task, small motor-cortical infarcts impaired skilled-reaching performance for up to 10 days. These results support that artery-targeted photothrombosis widens the penumbra while maintaining the ability to create localized infarcts useful for modeling post-stroke impairments.

7.
Biomed Opt Express ; 10(2): 584-599, 2019 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-30800501

RESUMO

Deep in vivo imaging of vasculature requires small, bright, and photostable fluorophores suitable for multiphoton microscopy (MPM). Although semiconducting polymer dots (pdots) are an emerging class of highly fluorescent contrast agents with favorable advantages for the next generation of in vivo imaging, their use for deep MPM has never before been demonstrated. Herein, we characterize the multiphoton properties of three pdot variants and perform deep in vivo MPM imaging of cortical rodent microvasculature. We find pdot brightness exceeds conventional fluorophores, including quantum dots, and their broad multiphoton absorption spectrum permits imaging at wavelengths better-suited for biological imaging and confers compatibility with a range of longer excitation wavelengths. This results in substantial improvements in signal-to-background ratio (>3.5-fold) and greater cortical imaging depths (z = 1,300 µm). Ultimately, pdots are a versatile tool for MPM due to their extraordinary brightness and broad absorption, enabling interrogation of deep structures in vivo.

8.
Artigo em Inglês | MEDLINE | ID: mdl-30691968

RESUMO

BACKGROUND: Functional magnetic resonance imaging (fMRI) in awake behaving mice is well positioned to bridge the detailed cellular-level view of brain activity, which has become available owing to recent advances in microscopic optical imaging and genetics, to the macroscopic scale of human noninvasive observables. However, though microscopic (e.g., two-photon imaging) studies in behaving mice have become a reality in many laboratories, awake mouse fMRI remains a challenge. Owing to variability in behavior among animals, performing all types of measurements within the same subject is highly desirable and can lead to higher scientific rigor. METHODS: We demonstrated blood oxygenation level-dependent fMRI in awake mice implanted with long-term cranial windows that allowed optical access for microscopic imaging modalities and optogenetic stimulation. We started with two-photon imaging of single-vessel diameter changes (n = 1). Next, we implemented intrinsic optical imaging of blood oxygenation and flow combined with laser speckle imaging of blood flow obtaining a mesoscopic picture of the hemodynamic response (n = 16). Then we obtained corresponding blood oxygenation level-dependent fMRI data (n = 5). All measurements could be performed in the same mice in response to identical sensory and optogenetic stimuli. RESULTS: The cranial window did not deteriorate the quality of fMRI and allowed alternation between imaging modalities in each subject. CONCLUSIONS: This report provides a proof of feasibility for multiscale imaging approaches in awake mice. In the future, this protocol could be extended to include complex cognitive behaviors translatable to humans, such as sensory discrimination or attention.


Assuntos
Imagem por Ressonância Magnética/métodos , Modelos Animais , Neuroimagem/métodos , Córtex Somatossensorial/fisiologia , Animais , Camundongos , Imagem Óptica/métodos , Optogenética/métodos , Córtex Somatossensorial/irrigação sanguínea , Vigília
9.
Eur Psychiatry ; 55: 109-115, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30469009

RESUMO

BACKGROUND: Schizotypy represents a cluster of personality traits consisting of magical beliefs, perceptual aberrations, disorganisation, and anhedonia. Schizotypy denotes a vulnerability for psychosis, one reason being psychosocial stress. High expressed emotion (EE), a rating of high criticism, hostility, and emotional over-involvement from a close relative, denotes psychosocial stress and vulnerability to psychosis, and is associated with schizotypy. This study aimed to decipher the relationship of schizotypy to perceived criticism and perceived praise in terms of affect and perceived EE. METHODS: Ninety-eight healthy participants listened to short audio-clips containing criticism, praise, and neutral comments from a stranger, and evaluated them in terms of the comments' arousal and personal relevance. Participants also answered self-report questionnaires of schizotypy, depression, mood, and perceived EE. Correlational analyses tested the relationship between schizotypy and the evaluations of criticism and praise. Mediation analyses then tested whether depression, positive mood, and perceived EE explained these relationships. RESULTS: Greater relevance of standard criticism correlated with higher positive schizotypy. This association was fully mediated by high depression and perceived irritability from a close relative. Lower relevance of standard praise correlated with higher cognitive disorganisation (another schizotypal trait). This relationship was partially mediated by low positive mood and high perceived intrusiveness from a close relative. CONCLUSION: Greater perceived criticism and lower perceived praise predict schizotypy in the healthy population. Affect and interpersonal sensitivity towards a close relative explain these relationships, such that depression increases perceived criticism, and positive mood increases perceived praise. Perceived EE defines the interpersonal nature of schizotypy.


Assuntos
Depressão , Emoções Manifestas , Conflito Familiar/psicologia , Hostilidade , Humor Irritável , Transtorno da Personalidade Esquizotípica , Adulto , Depressão/diagnóstico , Depressão/psicologia , Feminino , Humanos , Relações Interpessoais , Masculino , Testes Psicológicos , Transtorno da Personalidade Esquizotípica/diagnóstico , Transtorno da Personalidade Esquizotípica/psicologia , Autoeficácia , Inquéritos e Questionários
10.
Stroke ; 49(10): 2536-2540, 2018 10.
Artigo em Inglês | MEDLINE | ID: mdl-30355099

RESUMO

Background and Purpose- VWF (von Willebrand factor) strings mediate spontaneous platelet adhesion in the vascular lumen, which may lead to microthrombi formation and contribute to stroke pathology. However, the mechanism of VWF string attachment at the endothelial surface is unknown. We tested the novel hypothesis that VWF strings are tethered to the endothelial surface through an interaction between extracellular vimentin and the A2 domain of VWF. We further explored the translational value of blocking this interaction in a model of ischemic stroke. Methods- Human endothelial cells and pressurized cerebral arteries were stimulated with histamine to elicit VWF string formation. Recombinant proteins and antibodies were used to block VWF string formation. Mice underwent transient middle cerebral artery occlusion with reperfusion. Just before recanalization, mice were given either vehicle or A2 protein (recombinant VWF A2 domain) to disrupt the vimentin/VWF interaction. Laser speckle contrast imaging was used to monitor cortical perfusion. Results- Pressurized cerebral arteries produced VWF strings following histamine stimulation, which were reduced in arteries from Vim KO (vimentin knockout) mice. VWF string formation was significantly reduced in endothelial cells incubated with A2 protein or antivimentin antibodies. Lastly, A2 protein treatment significantly improved cortical reperfusion after middle cerebral artery occlusion. Conclusions- We provide the first direct evidence of cerebral VWF strings and demonstrate that extracellular vimentin significantly contributes to VWF string formation via A2 domain binding. Lastly, we show that pharmacologically targeting the vimentin/VWF interaction through the A2 domain can promote improved reperfusion after ischemic stroke. Together, these studies demonstrate the critical role of VWF strings in stroke pathology and offer new therapeutic targets for treatment of ischemic stroke.


Assuntos
Plaquetas/metabolismo , Acidente Vascular Cerebral/metabolismo , Vimentina/metabolismo , Fator de von Willebrand/metabolismo , Animais , Células Endoteliais/metabolismo , Infarto da Artéria Cerebral Média/metabolismo , Camundongos , Adesividade Plaquetária/fisiologia , Estresse Mecânico
11.
ACS Nano ; 12(10): 10383-10392, 2018 Oct 23.
Artigo em Inglês | MEDLINE | ID: mdl-30226980

RESUMO

Optical manipulation of colloidal nanoparticles and molecules is significant in numerous fields. Opto-thermoelectric nanotweezers exploiting multiple coupling among light, heat, and electric fields enables the low-power optical trapping of nanoparticles on a plasmonic substrate. However, the management of light-to-heat conversion for the versatile and precise manipulation of nanoparticles is still elusive. Herein, we explore the opto-thermoelectric trapping at plasmonic antennas that serve as optothermal nanoradiators to achieve the low-power (∼0.08 mW/µm2) and deterministic manipulation of nanoparticles. Specifically, precise optical manipulation of nanoparticles is achieved via optical control of the subwavelength thermal hot spots. We employ a femtosecond laser beam to further improve the heat localization and the precise trapping of single ∼30 nm semiconductor quantum dots at the antennas where the plasmon-exciton coupling can be tuned. With its low-power, precise, and versatile particle control, the opto-thermoelectric manipulation can have applications in photonics, life sciences, and colloidal sciences.

12.
Neurophotonics ; 5(3): 035003, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30137881

RESUMO

We present a dual-modality imaging system combining laser speckle contrast imaging and oxygen-dependent quenching of phosphorescence to simultaneously map cortical blood flow and oxygen tension ( pO2 ) in mice. Phosphorescence signal localization is achieved through the use of a digital micromirror device (DMD) that allows for selective excitation of arbitrary regions of interest. By targeting both excitation maxima of the oxygen-sensitive Oxyphor PtG4, we are able to examine the effects of excitation wavelength on the measured phosphorescence lifetime. We demonstrate the ability to measure the differences in pO2 between arteries and veins and large changes during a hyperoxic challenge. We dynamically monitor blood flow and pO2 during DMD-targeted photothrombotic occlusion of an arteriole and highlight the presence of an ischemia-induced depolarization. Chronic tracking of the ischemic lesion over eight days revealed a rapid recovery, with the targeted vessel fully reperfusing and pO2 returning to baseline values within five days. This system has broad applications for studying the acute and chronic pathophysiology of ischemic stroke and other vascular diseases of the brain.

13.
Neurobiol Learn Mem ; 152: 50-60, 2018 07.
Artigo em Inglês | MEDLINE | ID: mdl-29778761

RESUMO

Previous findings that skill learning is associated with the formation and preferential stabilization of new dendritic spines in cortex have raised the possibility that this preferential stabilization is a mechanism for lasting skill memory. We investigated this possibility in adult mice using in vivo two-photon imaging to monitor spine dynamics on superficial apical dendrites of layer V pyramidal neurons in motor cortex during manual skill learning. Spine formation increased over the first 3 days of training on a skilled reaching task, followed by increased spine elimination. A greater proportion of spines formed during the first 3 training days were lost if training stopped after 3, compared with 15 days. However, performance gains achieved in 3 training days persisted, indicating that preferential new spine stabilization was non-essential for skill retention. Consistent with a role in ongoing skill refinement, the persistence of spines formed early in training strongly predicted performance improvements. Finally, while we observed no net spine density change on superficial dendrites, the density of spines on deeper apical branches of the same neuronal population was increased regardless of training duration, suggestive of a potential role in the retention of the initial skill memory. Together, these results indicate dendritic subpopulation-dependent variation in spine structural responses to skill learning, which potentially reflect distinct contributions to the refinement and retention of newly acquired motor skills.


Assuntos
Espinhas Dendríticas/fisiologia , Memória/fisiologia , Córtex Motor/fisiologia , Destreza Motora , Animais , Masculino , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Córtex Motor/citologia , Imagem Óptica
14.
J Neurophysiol ; 120(1): 330-342, 2018 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-29641311

RESUMO

Everyday cognitive tasks are frequently performed under dual-task conditions alongside continuous sensorimotor coordinations (CSCs) such as driving, walking, or balancing. Observed interference in these dual-task settings is commonly attributed to demands on executive function or attentional resources, but the time course and reciprocity of interference are not well understood at the level of information-processing components. Here we used electrophysiology to study the detailed chronometry of dual-task interference between a visual oddball task and a continuous visuomanual tracking task. The oddball task's electrophysiological components were linked to underlying cognitive processes, and the tracking task served as a proxy for the continuous cycle of state monitoring and adjustment inherent to CSCs. Dual-tasking interfered with the oddball task's accuracy and attentional processes (attenuated P2 and P3b magnitude and parietal alpha-band event-related desynchronization), but errors in tracking due to dual-tasking accrued at a later timescale and only in trials in which the target stimulus appeared and its tally had to be incremented. Interference between cognitive tasks and CSCs can be asymmetric in terms of timing as well as affected information-processing components. NEW & NOTEWORTHY Interference between cognitive tasks and continuous sensorimotor coordination (CSC) has been widely reported, but this is the first demonstration that the cognitive operation that is impaired by concurrent CSC may not be the one that impairs the CSC. Also demonstrated is that interference between such tasks can be temporally asymmetric. The asynchronicity of this interference has significant implications for understanding and mitigating loss of mobility in old age, and for rehabilitation for neurological impairments.


Assuntos
Cognição , Desempenho Psicomotor , Córtex Sensório-Motor/fisiologia , Adulto , Atenção , Feminino , Mãos/fisiologia , Humanos , Masculino
15.
Cancer Cell ; 33(2): 187-201.e10, 2018 02 12.
Artigo em Inglês | MEDLINE | ID: mdl-29438695

RESUMO

Protein glycosylation provides proteomic diversity in regulating protein localization, stability, and activity; it remains largely unknown whether the sugar moiety contributes to immunosuppression. In the study of immune receptor glycosylation, we showed that EGF induces programmed death ligand 1 (PD-L1) and receptor programmed cell death protein 1 (PD-1) interaction, requiring ß-1,3-N-acetylglucosaminyl transferase (B3GNT3) expression in triple-negative breast cancer. Downregulation of B3GNT3 enhances cytotoxic T cell-mediated anti-tumor immunity. A monoclonal antibody targeting glycosylated PD-L1 (gPD-L1) blocks PD-L1/PD-1 interaction and promotes PD-L1 internalization and degradation. In addition to immune reactivation, drug-conjugated gPD-L1 antibody induces a potent cell-killing effect as well as a bystander-killing effect on adjacent cancer cells lacking PD-L1 expression without any detectable toxicity. Our work suggests targeting protein glycosylation as a potential strategy to enhance immune checkpoint therapy.


Assuntos
Anticorpos Monoclonais/farmacologia , Linfócitos do Interstício Tumoral/efeitos dos fármacos , Receptor de Morte Celular Programada 1/imunologia , Neoplasias de Mama Triplo Negativas/tratamento farmacológico , Neoplasias de Mama Triplo Negativas/imunologia , Animais , Linhagem Celular Tumoral , Feminino , Humanos , Linfócitos do Interstício Tumoral/imunologia , Camundongos Endogâmicos BALB C , N-Acetilglucosaminiltransferases/efeitos dos fármacos , N-Acetilglucosaminiltransferases/metabolismo , Neoplasias de Mama Triplo Negativas/metabolismo
16.
Q J Exp Psychol (Hove) ; 71(2): 424-434, 2018 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-27784196

RESUMO

Voices and static faces can be matched for identity above chance level. No previous face-voice matching experiments have included an inter-stimulus interval (ISI) exceeding 1 s. We tested whether accurate identity decisions rely on high-quality perceptual representations temporarily stored in sensory memory, and therefore whether the ability to make accurate matching decisions diminishes as the ISI increases. In each trial, participants had to decide whether an unfamiliar face and voice belonged to the same person. The face and voice stimuli were presented simultaneously in Experiment 1, and there was a 5-s ISI in Experiment 2, and a 10-s interval in Experiment 3. The results, analysed using multilevel modelling, revealed that static face-voice matching was significantly above chance level only when the stimuli were presented simultaneously (Experiment 1). The overall bias to respond same identity weakened as the interval increased, suggesting that this bias is explained by temporal contiguity. Taken together, the findings highlight that face-voice matching performance is reliant on comparing fast-decaying, high-quality perceptual representations. The results are discussed in terms of social functioning.


Assuntos
Associação , Face , Memória/fisiologia , Voz , Estimulação Acústica , Adolescente , Adulto , Viés , Feminino , Humanos , Masculino , Estimulação Luminosa , Fatores de Tempo , Adulto Jovem
17.
J Neurosci Methods ; 295: 68-76, 2018 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-29203409

RESUMO

BACKGROUND: Despite significant advancements of optical imaging techniques for mapping hemodynamics in small animal models, it remains challenging to combine imaging with spatially resolved electrical recording of individual neurons especially for longitudinal studies. This is largely due to the strong invasiveness to the living brain from the penetrating electrodes and their limited compatibility with longitudinal imaging. NEW METHOD: We implant arrays of ultraflexible nanoelectronic threads (NETs) in mice for neural recording both at the brain surface and intracortically, which maintain great tissue compatibility chronically. By mounting a cranial window atop of the NET arrays that allows for chronic optical access, we establish a multimodal platform that combines spatially resolved electrical recording of neural activity and laser speckle contrast imaging (LSCI) of cerebral blood flow (CBF) for longitudinal studies. RESULTS: We induce peri-infarct depolarizations (PIDs) by targeted photothrombosis, and show the ability to detect its occurrence and propagation through spatiotemporal variations in both extracellular potentials and CBF. We also demonstrate chronic tracking of single-unit neural activity and CBF over days after photothrombosis, from which we observe reperfusion and increased firing rates. COMPARISON WITH EXISTING METHOD(S): This multimodal platform enables simultaneous mapping of neural activity and hemodynamic parameters at the microscale for quantitative, longitudinal comparisons with minimal perturbation to the baseline neurophysiology. CONCLUSION: The ability to spatiotemporally resolve and chronically track CBF and neural electrical activity in the same living brain region has broad applications for studying the interplay between neural and hemodynamic responses in health and in cerebrovascular and neurological pathologies.


Assuntos
Isquemia Encefálica/diagnóstico por imagem , Isquemia Encefálica/fisiopatologia , Modelos Animais de Doenças , Eletrodos Implantados , Nanotecnologia/instrumentação , Imagem Óptica/instrumentação , Potenciais de Ação , Animais , Mapeamento Encefálico/instrumentação , Mapeamento Encefálico/métodos , Circulação Cerebrovascular , Desenho de Equipamento , Neuroimagem Funcional/instrumentação , Neuroimagem Funcional/métodos , Estudos Longitudinais , Masculino , Camundongos Endogâmicos C57BL , Imagem Multimodal/instrumentação , Imagem Multimodal/métodos , Nanotecnologia/métodos , Neurônios/fisiologia , Imagem Óptica/métodos , Acidente Vascular Cerebral/diagnóstico por imagem , Acidente Vascular Cerebral/fisiopatologia
18.
Small ; 13(38)2017 10.
Artigo em Inglês | MEDLINE | ID: mdl-28834225

RESUMO

By harnessing photoswitchable intersystem crossing (ISC) in spiropyran (SP) molecules, active control of plasmon-enhanced fluorescence in the hybrid systems of SP molecules and plasmonic nanostructures is achieved. Specifically, SP-derived merocyanine (MC) molecules formed by photochemical ring-opening reaction display efficient ISC due to their zwitterionic character. In contrast, ISC in quinoidal MC molecules formed by thermal ring-opening reaction is negligible. The high ISC rate can improve fluorescence quantum yield of the plasmon-modified spontaneous emission, only when the plasmonic electromagnetic field enhancement is sufficiently high. Along this line, extensive photomodulation of fluorescence is demonstrated by switching the ISC in MC molecules at Au nanoparticle aggregates, where strongly enhanced plasmonic hot spots exist. The ISC-mediated plasmon-enhanced fluorescence represents a new approach toward controlling the spontaneous emission of fluorophores near plasmonic nanostructures, which expands the applications of active molecular plasmonics in information processing, biosensing, and bioimaging.

19.
Tissue Eng Part A ; 23(21-22): 1251-1261, 2017 11.
Artigo em Inglês | MEDLINE | ID: mdl-28699397

RESUMO

Peripheral ischemia as a result of occlusive vascular disease is a widespread problem in patients older than the age of 65. Angiogenic therapies that can induce microvascular growth have great potential for providing a long-lasting solution for patients with ischemia and would provide an appealing alternative to surgical and percutaneous interventions. However, many angiogenic therapies have seen poor efficacy in clinical trials, suggesting that patients with long-term peripheral ischemia have considerable therapeutic resistance to angiogenic stimuli. Glioblastoma is one of the most angiogenic tumor types, inducing robust vessel growth in the area surrounding the tumor. One major angiogenic mechanism used by the tumor cells to induce blood vessel growth is the production of exosomes and other extracellular vesicles that can carry pro-angiogenic and immunomodulatory signals. Here, we explored whether the pro-angiogenic aspects of glioblastoma-derived exosomes could be harnessed to promote angiogenesis and healing in the context of peripheral ischemic disease. We demonstrate that the exosomes derived from glioblastoma markedly enhance endothelial cell proliferation and increase endothelial tubule formation in vitro. An analysis of the microRNA expression using next generation sequencing identified that exosomes contained a high concentration of miR-221. In addition, we found that glioblastoma exosomes contained significant amounts of the proteoglycans glypican-1 and syndecan-4, which can serve as co-receptors for angiogenic factors, including fibroblast growth factor-2 (FGF-2). In a hindlimb ischemia model in mice, we found that the exosomes promoted enhanced revascularization in comparison to control alginate gels and FGF-2 treatment alone. Taken together, our results support the fact that glioblastoma-derived exosomes have powerful effects in increasing revascularization in the context of peripheral ischemia.


Assuntos
Neoplasias Encefálicas/metabolismo , Exossomos/metabolismo , Glioblastoma/metabolismo , Isquemia/terapia , Neovascularização Fisiológica , Animais , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Exossomos/ultraestrutura , Fator 2 de Crescimento de Fibroblastos/farmacologia , Fator 2 de Crescimento de Fibroblastos/uso terapêutico , Membro Posterior/irrigação sanguínea , Membro Posterior/patologia , Células Endoteliais da Veia Umbilical Humana/efeitos dos fármacos , Células Endoteliais da Veia Umbilical Humana/metabolismo , Humanos , Isquemia/tratamento farmacológico , Camundongos Endogâmicos C57BL , Neovascularização Fisiológica/efeitos dos fármacos , RNA Neoplásico/metabolismo
20.
Biomed Opt Express ; 8(7): 3470-3481, 2017 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-28717582

RESUMO

We perform high-resolution, non-invasive, in vivo deep-tissue imaging of the mouse neocortex using multiphoton microscopy with a high repetition rate optical parametric amplifier laser source tunable between λ=1,100 and 1,400 nm. By combining the high repetition rate (511 kHz) and high pulse energy (400 nJ) of our amplifier laser system, we demonstrate imaging of vasculature labeled with Texas Red and Indocyanine Green, and neurons expressing tdTomato and yellow fluorescent protein. We measure the blood flow speed of a single capillary at a depth of 1.2 mm, and image vasculature to a depth of 1.53 mm with fine axial steps (5 µm) and reasonable acquisition times. The high image quality enabled analysis of vascular morphology at depths to 1.45 mm.

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