The Experts below are selected from a list of 6810 Experts worldwide ranked by ideXlab platform
Lihong V Wang - One of the best experts on this subject based on the ideXlab platform.
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calibration free in vivo transverse Blood Flowmetry based on cross correlation of slow time profiles from photoacoustic microscopy
Optics Letters, 2013Co-Authors: Yong Zhou, Konstantin Maslov, Jinyang Liang, Lihong V WangAbstract:We propose a cross-correlation-based method to measure Blood-flow velocity by using photoacoustic microscopy. Unlike in previous autocorrelation-based methods, the measured flow velocity here is independent of particle size. Thus an absolute flow velocity can be obtained without calibration. We first measured the flow velocity ex vivo, using defibrinated bovine Blood. Then flow velocities in vessels with different structures in a mouse ear were quantified in vivo. We further measured the flow variation in the same vessel and at a vessel bifurcation. All the experimental results indicate that our method can be used to accurately quantify Blood velocity in vivo.
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functional transcranial brain imaging by optical resolution photoacoustic microscopy
Journal of Biomedical Optics, 2009Co-Authors: Konstantin Maslov, Vassiliy Tsytsarev, Lihong V WangAbstract:Optical-resolution photoacoustic microscopy OR-PAM is applied to functional brain imaging in living mice. A near-diffraction-limited bright-field optical illumi- nation is employed to achieve micrometer lateral reso- lution, and a dual-wavelength measurement is utilized to extract the Blood oxygenation information. The variation in hemoglobin oxygen saturation sO2 along vascular branching has been imaged in a precapillary arteriolar tree and a postcapillary venular tree, respectively. To the best of our knowledge, this is the first report on in vivo volu- metric imaging of brain microvascular morphology and oxygenation down to single capillaries through intact mouse skulls. It is anticipated that: i chronic imaging enabled by this minimally invasive procedure will ad- vance the study of cortical plasticity and neurological dis- eases; ii revealing the neuroactivity-dependent changes in hemoglobin concentration and oxygenation will facili- tate the understanding of neurovascular coupling at the capillary level; and iii combining functional OR-PAM and high-resolution Blood Flowmetry will have the poten- tial to explore cellular pathways of brain energy metabolism. © 2009 Society of Photo-Optical Instrumentation Engineers. DOI: 10.1117/1.3194136
Toyoaki Murohara - One of the best experts on this subject based on the ideXlab platform.
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enhanced angiogenesis by transplantation of mesenchymal stem cell sheet created by a novel magnetic tissue engineering method
Arteriosclerosis Thrombosis and Vascular Biology, 2011Co-Authors: Masakazu Ishii, Yasushi Numaguchi, Rei Shibata, Tetsutaro Kito, Hirohiko Suzuki, Kazunori Shimizu, Akira Ito, Hiroyuki Honda, Toyoaki MuroharaAbstract:Objective— Therapeutic angiogenesis with cell transplantation represents a novel strategy for severe ischemic diseases. However, some patients have poor response to such conventional injection-based angiogenic cell therapy. Here, we investigated a therapeutic potential of mesenchymal stem cell (MSC) sheet created by a novel magnetite tissue engineering technology for reparative angiogenesis. Methods and Results— Human MSCs incubated with magnetic nanoparticle-containing liposomes were cultured, and a magnet was placed on the reverse side. Magnetized MSCs formed multilayered cell sheets according to magnetic force. Nude mice were subjected to unilateral hind limb ischemia and separated into 3 groups. For the control group, saline was injected into ischemic tissue. In the MSC-injected group, mice received magnetized MSCs by conventional needle injections without sheet formula as a control cell group. In the MSC-sheet group, MSC sheet was layered onto the ischemic tissues before skin closure. Blood flow recovery and the extent of angiogenesis were assessed by a laser Doppler Blood Flowmetry and histological capillary density, respectively. The MSC-sheet group had a greater angiogenesis in ischemic tissues compared to the control and MSC-injected groups. The angiogenic and tissue-preserving effects of MSC sheets were attributable to an increased expression of vascular endothelial growth factor and reduced apoptosis in ischemic tissues. In cultured MSCs, magnetic labeling itself inhibited apoptosis via a catalase-like antioxidative mechanism. Conclusion— MSC sheet created by the novel magnetic nanoparticle-based tissue engineering technology would represent a new modality for therapeutic angiogenesis and tissue regeneration.
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Role of Bradykinin, Nitric Oxide, and Angiotensin II Type 2 Receptor in Imidapril-Induced Angiogenesis
Hypertension (Dallas Tex. : 1979), 2007Co-Authors: Takahisa Kondo, Yasushi Numaguchi, Koichi Kobayashi, Mika Aoki, Natsuo Inoue, Kenji Okumura, Toyoaki MuroharaAbstract:The angiotensin II (Ang II)-Ang II type 1 receptor pathway is proangiogenic, whereas studies showed that some angiotensin-converting enzyme inhibitors also stimulate angiogenesis in the setting of tissue ischemia, leaving a controversy of Ang II-mediated angiogenesis. We investigated whether an angiotensin-converting enzyme inhibitor imidapril-induced angiogenesis might be mediated via the tissue bradykinin pathway. To rule out the conventional effects of Ang II on angiogenesis, we used Ang II type 1a receptor knockout (AT1aKO) mice. We examined the effects of the angiotensin-converting enzyme inhibitor imidapril on angiogenesis in a hindlimb ischemia model using AT1aKO mice. After induction of hindlimb ischemia, AT1aKO mice were treated with or without imidapril (1.0 or 0.1 mg/kg per day for 21 days). Angiogenesis was quantified by laser Doppler Blood Flowmetry and capillary density. Angiogenesis was reduced in AT1aKO mice compared with wild-type mice. Imidapril with either low or high doses enhanced angiogenesis in AT1aKO mice ( P N G -nitro-l-arginine methyl ester; 20 mg/kg per day) moderately attenuated the imidapril-mediated angiogenesis. RT-PCR revealed that vascular endothelial growth factor receptor 2 mRNA was reduced with PD123319, DesArg9-[Leu8]-bradykinin, or Hoechst 140, and vascular endothelial growth factor mRNA abundance was suppressed with PD123319 or DesArg9-[Leu8]-bradykinin. In conclusion, imidapril elicited angiogenesis in the setting of tissue ischemia in AT1aKO mice. This angiogenic effect might involve the Ang II-Ang II type 2 receptor pathway in addition to the bradykinin-B1 and bradykinin-B2 receptor/NO-dependent pathways.
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derivation of functional endothelial progenitor cells from human umbilical cord Blood mononuclear cells isolated by a novel cell filtration device
Stem Cells, 2004Co-Authors: Mika Aoki, Mikitomo Yasutake, Toyoaki MuroharaAbstract:Endothelial progenitor cells (EPCs) can differentiate from mononuclear cells (MNCs) of adult human peripheral Blood, bone marrow, and cord Blood during culture. Although MNCs are usually isolated by a Ficoll gradient centrifuge method, this method is time-consuming, and Blood is easily contaminated. We developed a novel cell filtration device (StemQuick™E, Asahi Kasei Medical, Oita, Tokyo, Japan) to isolate MNCs from human cord Blood and examined whether functional EPCs could differentiate from MNCs isolated by this device. Recovery rates of MNCs, CD34+ and CD133+ progenitor cells, were significantly greater in the StemQuick™E method than in the Ficoll method. During MNC culture, spindle-shaped attaching cells developed, and most of these cells incorporated DiI-acetylated low-density lipoprotein and showed positive binding to fluorescein isothiocyanate–lectin. Reverse transcription–polymerase chain reaction analysis revealed that attaching cells expressed various progenitor and endothelial lineage markers such as KDR, CD31, endothelial cell nitric oxide synthase, CD133, and LOX-1. Culture-expanded EPCs were isolated and labeled with a green fluorescent dye, PKH2-GL, and cocultured with human umbilical vein endothelial cells (HUVECs). EPCs formed angiogenesis-like networks together with HUVECs in 3D matrix gel. Finally, EPCs (3 × 105) were implanted into ischemic hindlimb of nude rats (n = 3), and laser Doppler Blood Flowmetry (LDBF) revealed that the ratio of ischemic to normal limb LDBF was significantly greater in EPC-transplanted animals compared with controls receiving saline. In conclusion, the novel cell filtration device, StemQuick™E, is a useful tool to isolate MNCs from human cord Blood. Moreover, MNCs obtained by this filter system can give rise to functional EPCs.
Konstantin Maslov - One of the best experts on this subject based on the ideXlab platform.
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calibration free in vivo transverse Blood Flowmetry based on cross correlation of slow time profiles from photoacoustic microscopy
Optics Letters, 2013Co-Authors: Yong Zhou, Konstantin Maslov, Jinyang Liang, Lihong V WangAbstract:We propose a cross-correlation-based method to measure Blood-flow velocity by using photoacoustic microscopy. Unlike in previous autocorrelation-based methods, the measured flow velocity here is independent of particle size. Thus an absolute flow velocity can be obtained without calibration. We first measured the flow velocity ex vivo, using defibrinated bovine Blood. Then flow velocities in vessels with different structures in a mouse ear were quantified in vivo. We further measured the flow variation in the same vessel and at a vessel bifurcation. All the experimental results indicate that our method can be used to accurately quantify Blood velocity in vivo.
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functional transcranial brain imaging by optical resolution photoacoustic microscopy
Journal of Biomedical Optics, 2009Co-Authors: Konstantin Maslov, Vassiliy Tsytsarev, Lihong V WangAbstract:Optical-resolution photoacoustic microscopy OR-PAM is applied to functional brain imaging in living mice. A near-diffraction-limited bright-field optical illumi- nation is employed to achieve micrometer lateral reso- lution, and a dual-wavelength measurement is utilized to extract the Blood oxygenation information. The variation in hemoglobin oxygen saturation sO2 along vascular branching has been imaged in a precapillary arteriolar tree and a postcapillary venular tree, respectively. To the best of our knowledge, this is the first report on in vivo volu- metric imaging of brain microvascular morphology and oxygenation down to single capillaries through intact mouse skulls. It is anticipated that: i chronic imaging enabled by this minimally invasive procedure will ad- vance the study of cortical plasticity and neurological dis- eases; ii revealing the neuroactivity-dependent changes in hemoglobin concentration and oxygenation will facili- tate the understanding of neurovascular coupling at the capillary level; and iii combining functional OR-PAM and high-resolution Blood Flowmetry will have the poten- tial to explore cellular pathways of brain energy metabolism. © 2009 Society of Photo-Optical Instrumentation Engineers. DOI: 10.1117/1.3194136
Masahiro Tsuji - One of the best experts on this subject based on the ideXlab platform.
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Dose-Dependent Effect of Intravenous Administration of Human Umbilical Cord-Derived Mesenchymal Stem Cells in Neonatal Stroke Mice
Frontiers in Neurology, 2018Co-Authors: Emi Tanaka, Yoshiaki Sato, Mariko Harada-shiba, Yuko Ogawa, Takeo Mukai, Takashi Hamazaki, Tokiko Nagamura-inoue, Haruo Shintaku, Masahiro TsujiAbstract:Neonatal brain injury induced by stroke causes significant disability, including cerebral palsy, and there is no effective therapy for stroke. Recently, mesenchymal stem cells (MSCs) have emerged as a promising tool for stem cell-based therapies. In this study, we examined the safety and efficacy of intravenously administered human umbilical cord-derived MSCs (UC-MSCs) in neonatal stroke mice. Pups underwent permanent middle cerebral artery occlusion at postnatal day 12 (P12), and low-dose (1 × 104) or high-dose (1 × 105) UC-MSCs were administered intravenously 48 h after the insult (P14). To evaluate the effect of the UC-MSC treatment, neurological behavior and cerebral Blood flow were measured, and neuroanatomical analysis was performed at P28. To investigate the mechanisms of intravenously injected UC-MSCs, systemic Blood Flowmetry, in vivo imaging and human brain-derived neurotrophic factor (BDNF) measurements were performed. Functional disability was significantly improved in the high-dose UC-MSC group when compared with the vehicle group, but cerebral Blood flow and cerebral hemispheric volume were not restored by UC-MSC therapy. The level of exogenous human BDNF was elevated only in the cerebrospinal fluid of one pup 24 h after UC-MSC injection, and in vivo imaging revealed that most UC-MSCs were trapped in the lungs and disappeared in a week without migration toward the brain or other organs. We found that systemic Blood flow was stable over the 10 min after cell administration and that there were no differences in mortality among the groups. Immunohistopathological assessment showed that the percent area of Iba1-positive staining in the peri-infarct cortex was significantly reduced with the high-dose UC-MSC treatment compared with the vehicle treatment. These results suggest that intravenous administration of UC-MSCs is safe for a mouse model of neonatal stroke and improves dysfunction after middle cerebral artery occlusion by modulating the microglial reaction in the peri-infarct cortex.
Yong Zhou - One of the best experts on this subject based on the ideXlab platform.
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calibration free in vivo transverse Blood Flowmetry based on cross correlation of slow time profiles from photoacoustic microscopy
Optics Letters, 2013Co-Authors: Yong Zhou, Konstantin Maslov, Jinyang Liang, Lihong V WangAbstract:We propose a cross-correlation-based method to measure Blood-flow velocity by using photoacoustic microscopy. Unlike in previous autocorrelation-based methods, the measured flow velocity here is independent of particle size. Thus an absolute flow velocity can be obtained without calibration. We first measured the flow velocity ex vivo, using defibrinated bovine Blood. Then flow velocities in vessels with different structures in a mouse ear were quantified in vivo. We further measured the flow variation in the same vessel and at a vessel bifurcation. All the experimental results indicate that our method can be used to accurately quantify Blood velocity in vivo.