86 results on '"Hideyuki, Niimi"'
Search Results
2. Blood cell filtration test at low flow rates for clinical applications
- Author
-
Hideyuki Niimi, Yoshihiro Kuriyama, Tohru Sawada, Saburo Yamaguchi, Shi-Jia Gao, and Takao Shimizu
- Subjects
medicine.medical_specialty ,Physiology ,business.industry ,Hematology ,Differential pressure ,Surgery ,Volumetric flow rate ,law.invention ,Blood cell ,Red blood cell ,medicine.anatomical_structure ,Rheology ,law ,Physiology (medical) ,medicine ,Cardiology and Cardiovascular Medicine ,business ,Filtration ,Biomedical engineering - Published
- 2016
- Full Text
- View/download PDF
3. Microhemodynamic indices to evaluate the effectiveness of herbal medicine in diabetes: A comparison between alpha-mangostin and curcumin in the retina of type 2 diabetic rats
- Author
-
Jariyapongskul, Amporn, primary, Areebambud, Chonticha, additional, and Hideyuki, Niimi, additional
- Published
- 2018
- Full Text
- View/download PDF
4. Cross-Sectional Shape of Rat Mesenteric Arterioles at Branching Studied by Confocal Laser Microscopy
- Author
-
Atushi Nakano, Hideyuki Niimi, and Motomu Minamiyama
- Subjects
Laser Microscopy ,Materials science ,business.industry ,Mechanical Engineering ,Confocal ,Branching (polymer chemistry) ,Industrial and Manufacturing Engineering ,Microcirculation ,Cross section (geometry) ,Optics ,medicine.anatomical_structure ,Arteriole ,medicine.artery ,Confocal laser scanning microscopy ,medicine ,business ,Mesentery ,Biomedical engineering - Published
- 2006
- Full Text
- View/download PDF
5. Heterogeneity of capillary flow in the retrograde microcirculation induced in rat limb by arteriovenous shunting
- Author
-
Hideyuki Niimi, Junji Seki, Atushi Nakano, and Yutaka Komai
- Subjects
Male ,Erythrocytes ,Angiogenesis ,Arterial Occlusive Diseases ,Hindlimb ,Models, Biological ,Biochemistry ,Microcirculation ,Arteriovenous Shunt, Surgical ,Occlusion ,Animals ,Medicine ,Rats, Wistar ,Microscopy, Video ,business.industry ,Cell Biology ,Blood flow ,Anatomy ,Arterial occlusion ,Capillaries ,Rats ,Shunting ,Microscopy, Fluorescence ,Regional Blood Flow ,Cardiology and Cardiovascular Medicine ,business ,Perfusion ,Blood Flow Velocity - Abstract
Arteriovenous (AV) fistulas have been used clinically for improving adjunctive bypass patency. Such AV shunting induces retrograde flow in the microvascular network, which may induce microvascular remodeling and angiogenesis at the chronic phase. This paper was aimed to examine heterogeneity of blood flow among capillaries in the retrograde microcirculation induced by AV shunting. An AV anastomosis was created in rat hind limb. Using a dual window method or frame-by-frame technique on the fluorescence microscopic video images, we measured velocities of red blood cells (RBCs) flowing in the capillary network in three flow conditions: control (normal flow), arterial occlusion, and AV shunting (retrograde flow). For each flow condition, RBC velocities were obtained in 155 capillaries of 6 rats. By classifying all the capillaries into four groups based on the levels of RBC velocity in the occlusion state, we evaluated the mean velocities, coefficient of variation (CV), and histograms for each group of capillaries. The mean velocity and CV in each group changed significantly from the control to AV shunting states. Especially, most significant changes appeared in capillary groups where the superficial femoral artery or its collateral arteries might have a direct influence. Though the AV shunting improved capillary perfusion in the mean level, major parts of capillaries still remained at low perfusion.
- Published
- 2005
- Full Text
- View/download PDF
6. Velocity Profiles of Pulsatile Blood Flow in Arterioles with Bifurcation and Confluence in Rat Mesnetery Measured by Particle Image Velocimetry
- Author
-
Hideyuki Niimi, Motomu Minamiyama, Junji Seki, Atushi Nakano, and Yasuhiko Sugii
- Subjects
Optics ,Materials science ,Particle image velocimetry ,business.industry ,Mechanical Engineering ,Confluence ,Pulsatile blood flow ,business ,Industrial and Manufacturing Engineering ,Bifurcation ,Biomedical engineering ,Microcirculation - Published
- 2005
- Full Text
- View/download PDF
7. Blood Flow Velocity Measurement in the Microcirculation Using Highly Accurate Iterative PIV (2nd Report, Analysis of Ensemble Averaged Velocity in Rat Mesenteric Arterioles)
- Author
-
Shigeru Nishio, Hideyuki Niimi, Motomu Minamiyama, Yasuhiko Sugii, Atsushi Nakano, and Koji Okamoto
- Subjects
Near wall ,Materials science ,Mechanical Engineering ,Flow (psychology) ,Blood flow ,Condensed Matter Physics ,Microcirculation ,Red blood cell ,medicine.anatomical_structure ,Arteriole ,medicine.artery ,Temporal resolution ,medicine ,Shear stress ,Biomedical engineering - Abstract
Blood flow in microvessels, such as arterioles, capillaries and venules, whose diameter ranges from 5 to 50 μm, is responsible for the maintenance of tissue and organ functions. The measurement of microvascular blood flow velocity with high measurement accuracy is essential for basic and clinical studies in the assessment of flow shear stress at the vascular wall in relation to substance exchange between blood and tissue. This paper aimed to evaluate the velocity field of blood flow in microvessels with high spatial and temporal resolution. By using micro PIV system, the velocity distributions of red blood cells flowing in rat mesenteric arterioles, including near the wall in the axisymmetric plane, were obtained. Ensemble averaged time-series of velocity profiles in the cross-sections were calculated for comparison. It was shown that the arteriole velocity profile was blunt in the center region of the vessel cross-section while it was steep in the near wall region.
- Published
- 2004
- Full Text
- View/download PDF
8. Response of cerebral neocapillaries to acetylcholine: an intravital microscopic observation
- Author
-
Takashi Yamakawa, Hideyuki Niimi, and Kolammal Nageswari
- Subjects
medicine.medical_specialty ,biology ,Wild type ,Male mice ,General Medicine ,Anatomy ,Microscopic observation ,Red blood cell ,medicine.anatomical_structure ,Endocrinology ,Cerebral cortex ,Internal medicine ,medicine ,biology.protein ,Platelet-derived growth factor receptor ,Acetylcholine ,Intravital microscopy ,medicine.drug - Abstract
The purpose of this study was to examine the response of cerebral neocapillaries to acetylcholine (ACh) in mice. Wild type male mice were used. After anesthesia, a small area of the bone over the parietal cortex was removed to expose the cerebral cortex. The gel–nylon mesh sandwich system was placed over the exposed area. The growth factors bFGF and PDGF were used at a concentration of 6 ng/ml. After the surgical area was covered with a polyurethane biomembrane, the skin was closed with sutures. After 28 days of incubation, the neocapillaries were topically suffused with ACh and the responses of the vascular diameter and red blood cell (RBC) velocity were evaluated using intravital video microscopy. A control group was included to examine the responses of the pial vessels to ACh. A significant increase in vascular diameter and RBC velocity was observed in the control group, while the neocapillaries failed to show anything significant in the bFGF group. However, a significant increase in RBC velocity from the baseline value was observed in the PDGF group. It is suggested that the neocapillaries might have matured in the PDGF group with the formation of pericytes/smooth muscle cell function (SMC), leading to relaxation via the cGMP pathway.
- Published
- 2002
- Full Text
- View/download PDF
9. [Untitled]
- Author
-
K. Nageswari, T. Yamakawa, Hideyuki Niimi, and Saburo Yamaguchi
- Subjects
Cancer Research ,Platelet-derived growth factor ,biology ,Red Cell ,Physiology ,Angiogenesis ,Growth factor ,medicine.medical_treatment ,Clinical Biochemistry ,Basic fibroblast growth factor ,Anatomy ,Andrology ,chemistry.chemical_compound ,chemistry ,medicine ,biology.protein ,Fluorescein isothiocyanate ,Incubation ,Platelet-derived growth factor receptor - Abstract
To assess the responses of different growth factors on cerebral neocapillary density (NCD), cerebral angiogenesis was induced in mice using growth factors, basic fibroblast growth factor (bFGF) and platelet-derived growth factor (PDGF) at a concentration of 6 ng/ml each. Intravital fluorescence videomicroscopy was used to quantitatively evaluate microhemodynamic parameters such as diameter and red cell velocity. The gel–nylon mesh-sandwich system was implanted over the exposed cortex. After incubation for different periods of time (days 7, 14 or 28), fluorescein isothiocyanate (FITC)-labeled red cells were injected through a carotid artery and the neocapillaries on the upper surface of the nylon mesh were observed under a fluorescence videomicroscope. Based on the recorded videoimages, we evaluated the density, diameter and red cell velocity of the neocapillaries. The NCD in the bFGF group on day 7 was significantly higher than that in the PDGF group on day 7 (P < 0.01). The NCD (index) reached 100% on day 14, while it reduced significantly in both the groups on day 28. The neocapillary diameter was greater than that of the pre-existing capillaries on day 7. On day 14, a clear difference appeared in the capillary density between large and small vessels. The red cell velocity increased with the number of days after incubation. The response of cerebral neocapillaries to acetylcholine was measured after 28 days of incubation with growth factor bFGF and with PDGF. The red cell velocity increased significantly from its basal value in the PDGF group. These results suggest that the neocapillaries in the PDGF group matured earlier than those in the bFGF group.
- Published
- 2002
- Full Text
- View/download PDF
10. 122 Fluorescence Videomicroscopic Visualization of Organ Neovascularisation with Special Reference to Cerebral Angiogenesis
- Author
-
Hideyuki Niimi and Geetanjali Ranade
- Subjects
Pathogenesis ,Pathology ,medicine.medical_specialty ,Vascular network ,Angiogenesis ,cardiovascular system ,medicine ,Biology ,Visualization - Abstract
The recruitment of new blood vessels in living tissues is essential for the pathogenesis and prognosis of organ disorders.The present study is concerned with intravital observations of newly formed vascular network in mouse brain, using fluo-rescence video-imaging. This visualization technique is a useful tool to study morphology and physiology of the newly developed vessels. The information obtained from the video-image includes the morphology of vascular network, the time required to develop blood vessels, and the velocity of red blood cells flowing in blood vessels.
- Published
- 1999
- Full Text
- View/download PDF
11. In vivo observation of leukocyte adherence in asthmatic rats
- Author
-
Hideyuki Niimi, Q.H. Hu, H. Miao, Q.F. Xue, and F.Y. Zhuang
- Subjects
Pathology ,medicine.medical_specialty ,Allergy ,Endothelium ,Physiology ,Cell adhesion molecule ,business.industry ,Inflammation ,Hematology ,respiratory system ,medicine.disease ,respiratory tract diseases ,medicine.anatomical_structure ,Bronchial hyperresponsiveness ,In vivo ,Physiology (medical) ,Immunology ,cardiovascular system ,medicine ,medicine.symptom ,Cardiology and Cardiovascular Medicine ,business ,Infiltration (medical) ,Blood vessel - Abstract
Inflammation of the airway is thought to be one of the main factors contributing to the bronchial hyperresponsiveness which is characteristic for allergic asthma. Leukocyte adhered to vascular endothelium, which is caused by the interaction of adhesion molecules, is necessary for inflammatory cells infiltration. To elucidate the mechanism of leukocyte infiltration in asthma, we developed an animal model of asthma by using Wistar rats. In this model the leukocyte adhered to tracheal venular endothelium was assessed by in vivo microscopic observation. The results showed that the number of leukocytes adhered to tracheal venular endothelium increased significantly in asthmatic rats, as compared with those of controls, and it was accompanied by a significant inflammatory cell infiltration in lung tissue. It is concluded that the increase of leukocyte adhered to venular endothelium is pivotal in inflammatory cell infiltration in asthmatic rats. Copyright © 1996 Elsevier Science Ltd
- Published
- 1996
- Full Text
- View/download PDF
12. Cell-free plasma layer in cerebral microvessels
- Author
-
Saburo Yamaguchi, Takashi Yamakawa, and Hideyuki Niimi
- Subjects
Erythrocytes ,Materials science ,Physiology ,Flow tracer ,Plasma ,chemistry.chemical_compound ,Optics ,Physiology (medical) ,medicine ,Animals ,Fluorescein isothiocyanate ,Red Cell ,business.industry ,Microcirculation ,Radius ,Shear rate ,Red blood cell ,medicine.anatomical_structure ,Microscopy, Fluorescence ,chemistry ,Cerebrovascular Circulation ,Cats ,business ,Layer (electronics) ,Blood Flow Velocity ,Biomedical engineering - Abstract
Two diameters of vessel and red cell column in cerebral microvessels (> 29.8 microns in diameter) of cat were measured together with red cell velocity, using a two fluorescent tracer method. A fluorescein isothiocyanate (FITC)-labeled red cell was adopted as a flow tracer to measure the cell velocity with a dual window technique. Based on the fluorescence image, the red cell column diameter was measured. Plasma was stained with rhodamine-B isothiocyanate (RITC)-labeled dextran to measure the vessel diameter. The thickness of the cell-free plasma layer could be determined from the difference of the two diameters. The obtained thickness of the cell-free layer was not described by a simple function of vessel diameter or red cell velocity; it was dependent on the pseudo shear rate defined by the ratio of cell velocity to vessel radius. The layer thickness increased with a decrease in the pseudo shear rate.
- Published
- 1992
- Full Text
- View/download PDF
13. Increased capillary vascularity in the femur of aged rats by exercise training
- Author
-
Natchaya Wongeakin, Sheepsumon Viboolvorakul, Sukanya Eksakulkla, Hideyuki Niimi, and Suthiluk Patumraj
- Subjects
Male ,medicine.medical_specialty ,Pathology ,Aging ,Swimming exercise ,Confocal ,Urology ,medicine.disease_cause ,Biochemistry ,Microcirculation ,chemistry.chemical_compound ,Vascularity ,Malondialdehyde ,Physical Conditioning, Animal ,Medicine ,Animals ,Femur ,Rats, Wistar ,Swimming ,Microscopy, Confocal ,business.industry ,Cell Biology ,Capillaries ,Rats ,Oxidative Stress ,chemistry ,Liver ,medicine.symptom ,Cardiology and Cardiovascular Medicine ,business ,Perfusion ,Oxidative stress - Abstract
During aging, bone loss occurs in association with alteration of blood perfusion in the tissue. A number of studies have shown that repaired blood perfusion in various organs was improved by regular exercise, but the effect of exercise on bone microcirculation has not been studied fully yet. This study aimed to investigate the effect of exercise training on capillary vascularity in rat femur by directly observing the bone microcirculation under a laser scanning confocal microscope. Male Wistar rats were divided into three groups: sedentary-young (aged 4-6 months), sedentary-aged (aged 20-22 months) and trained-aged (aged 20-22 months). The exercise program included swimming training 5 days/week for 8 weeks. Using our newly devised window chamber, we directly observed the femur microcirculation of each group under a laser scanning confocal microscopic system. Based on the fluorescent image of microvasculature recorded at the surface of the femur, bone capillary vascularity (CV) was measured using computer software. Liver malondialdehyde (MDA) level was also measured to examine the relationship between CV and oxidative stress in aged rats. In the sedentary-aged group, the CV significantly decreased, but the MDA level significantly increased, compared with sedentary-young group. In the trained-aged group, CV was significantly higher, whereas the MDA level was significantly lower, compared with the sedentary-aged group. In both sedentary-young and sedentary-aged rats, the CV was linearly correlated with the MDA level. In conclusion, the swimming exercise could attenuate aged-induced suppression of CV, closely related to exercise-ameliorated oxidative stress in aged.
- Published
- 2009
14. Cerebral blood flow patterns at major vessel bifurcations and aneurysms in rats
- Author
-
Haruhiko Kikuchi, Hideyuki Nakatani, Nobuo Hashimoto, Yoo Kang, Hideyuki Niimi, Naohiro Yamazoe, and Saburo Yamaguchi
- Subjects
Male ,Motion Pictures ,Hemodynamics ,Aneurysm ,medicine.artery ,Animals ,Medicine ,cardiovascular diseases ,Common carotid artery ,business.industry ,Videotape Recording ,Intracranial Aneurysm ,Rats, Inbred Strains ,Anatomy ,Cerebral Arteries ,medicine.disease ,Microspheres ,Rats ,Apex (geometry) ,medicine.anatomical_structure ,Cerebral blood flow ,Cerebrovascular Circulation ,cardiovascular system ,Rheology ,business ,Perfusion ,Body orifice ,Artery - Abstract
✓ Cerebral arterial bifurcations in rats were treated to induce cerebral aneurysms experimentally, and flow patterns of latex particles introduced under a constant flow rate were analyzed with a 16-mm cine-camera and videocassette recorder. Cerebral aneurysms were produced by ligating one common carotid artery, inducing experimental hypertension, and feeding the animals β-aminopropionitrile. After perfusion and fixation, samples of cerebral arterial bifurcations with shallow invaginations and with small aneurysms were obtained and used for analysis. Bifurcations in rats without experimental treatment were used as control specimens. Flow studies in the control bifurcations showed that the apical intimal pad, not the apex itself, acted as the flow divider. Small particles tended to accumulate at the region just distal to the apical intimal pad, where the initial aneurysmal changes are known to occur. This indicates stagnation of flow at that site. In the bifurcations with shallow invaginations and small aneurysms, a marked pressure gradient was present at the proximal end of the aneurysm orifice. A tendency for stagnation of small particles near the aneurysm wall was also observed. The wall shear stress was highest at the distal end of the aneurysmal orifice, which may be responsible for the development of these lesions.
- Published
- 1991
- Full Text
- View/download PDF
15. Blood flow regulation in the cerebral microvasculature with an arcadal network: a numerical simulation
- Author
-
Hideyuki, Niimi, Yutaka, Komai, and Saburo, Yamaguchi
- Subjects
Regional Blood Flow ,Cerebrovascular Circulation ,Microcirculation ,Cats ,Animals ,Brain ,In Vitro Techniques ,Models, Biological ,Capillaries - Abstract
Blood flow regulation in the cerebral microvasculature with an arcadal network was investigated using a numerical simulation. A mathematical model for blood flow in the arcadal network, based on in vivo data of cat cerebral microvasculature and flow velocity was developed. The network model consists of 45 vessel segments and 25 branching points. To simulate microvascular response to blood flow, non-reactive (solid), cerebral arteriole-like, or skeletal muscle arteriole-like responses to wall shear stress were taken into account. Numerical calculation was carried out in the flow condition where the inlet (arterial) pressure was changed from 60 to 120 mmHg. Flow-rate in each efferent vessel and the mean flow-rate over all efferent vessels were evaluated for assessment of blood supply to the local area of cerebral tissue. The simulation demonstrated the wall shear stress-induced vasodilation in the arcadal network worked to maintain the blood flow at a constant level with pressure variable in a wide range. It is suggested that an individual microvessel (segment) should join in the regulatory process of flow, interacting with other microvessels (cooperative regulation).
- Published
- 2007
16. Chronic changes of the iris microvasculature of streptozotocin-induced diabetic rats using fluorescence videomicroscopy
- Author
-
Amporn, Jariyapongskul, Tippawan, Rungjaroen, Ngamjit, Kasetsuwan, Suthiluk, Pathumraj, and Hideyuki, Niimi
- Subjects
Male ,Microscopy, Video ,Microcirculation ,Iris ,Streptozocin ,Diabetes Mellitus, Experimental ,Rats ,Chronic Disease ,Cell Adhesion ,Leukocytes ,Animals ,Endothelium, Vascular ,Lipid Peroxidation ,Rats, Wistar ,Diabetic Angiopathies - Abstract
This study was aimed to investigate chronic changes of the iris microvasculature in streptozotocin (STZ)-induced diabetic rats. Diabetes was induced in male Wistar-Furth rats by intravenous injection of STZ (55 mg/kg.bw). The rats were divided into control (CON) and diabetic (STZ) groups. The experiments were performed at 8, 12, 24 and 36 weeks after the injection of STZ. The iris microcirculation was visualized under a fluorescence videomicroscope. Intraluminal diameters of microvessels were measured based on the FITC-dextran images. Leukocyte adhesion to the microvascular endothelium was evaluated by counting leukocytes (labeled with rhodamine 6G). The iris blood perfusion was measured using laser Doppler flowmetry. Tissue lipid peroxidation of the eye was evaluated. The results demonstrated that the lipid peroxidation increased significantly after the injection of STZ. Both the diameters of arterioles (or precapillaries) and the iris blood perfusion decreased significantly in STZ rats, compared to the control levels. Adherent leukocytes increased significantly at 8, 12, 24 and 36 week after the injection of STZ, compared with the control levels. This indicates that the increased in oxygen-derived free radicals may be a major contributor for iris vascular endothelial dysfunction in diabetes mellitus, including leukocyte adhesion and reducing the arteriolar diameter. The present model may be useful for assessing long-term effects of therapeutic agents on diabetic retinopathy.
- Published
- 2006
17. Microembolic flow disturbances in the cerebral microvasculature with an arcadal network: a numerical simulation
- Author
-
Hideyuki, Niimi, Yutaka, Komai, Saburo, Yamaguchi, and Junji, Seki
- Subjects
Intracranial Embolism ,Cerebrovascular Circulation ,Microcirculation ,Cats ,Models, Cardiovascular ,Animals ,Stress, Mechanical ,Blood Flow Velocity - Abstract
Flow disturbance due to microembolism in the cerebral microvasculature with an arcadal network was studied by a numerical simulation. A mathematical model for flow in the arcadal network was developed, based on in vivo data of cat cerebral microvasculature and flow velocity. The network model consisted of 45 vessel segments, and 25 branching points. To simulate microvascular responses to blood flow, the following three types of responses to wall shear stress were considered; non-reactive (solid-like), cerebral arteriole, and skeletal muscle arteriole-like responses. The numerical calculation was carried out in the condition where a feeding arteriole was occlused. Flow changes in efferent vessels were evaluated for assessment of blood supply to the local area of cerebral tissue. The present simulation has demonstrated that blood flow in efferent vessels was influenced by the topology of the vascular network and the response pattern in single vessels. The arcadal structure of arterioles might be most effective in response to flow disturbances in efferent vessels.
- Published
- 2006
18. Effects of Yahom on the regional cerebral blood flow in rat using fluorescence videomicroscopy
- Author
-
Amporn, Jariyapongskul, Suthiluk, Pathumraj, and Hideyuki, Niimi
- Subjects
Male ,Vasodilation ,Microscopy, Video ,Plant Extracts ,Cerebrovascular Circulation ,Animals ,Blood Pressure ,Medicine, Traditional ,Plant Preparations ,Rats, Wistar ,Thailand ,Blood Flow Velocity ,Rats - Abstract
This study was conducted to investigate effects of Yahom on the regional cerebral blood flow (rCBF) in rats using fluorescence videomicroscopy. Male Wistar Furth rats weighing 200-250 g were used, and divided into three groups: experimental I, II and control groups. The experimental I and II groups received single oral administration of Yahom 2 and 4 g/kg.bw, and topical application of Yahom on the pial cerebral cortex, respectively, while the control group received oral administration of 1 ml of 5% Tween. The rCBF was monitored using laser Doppler flowmetry at different periods (5-120 minutes) after the administration of Yahom or Tween. The mean arterial pressure (MAP) was measured through a femoral artery. The cerebral microcirculation was observed and recorded under an intravital fluorescence videomicroscopic system. The arteriolar diameter was measured based on the recorded videomicroscopic images. The MAP and rCBF increased after the oral administration of Yahom, while they did not alter in the control group. The maximum responses of MAP and rCBF were approximately 16% and 33% at 45 min and 30 min after the administration of Yahom 4 g/kg.bw, respectively. The topical application of Yahom induced vasodilation in the pial microvessels. In conclusion, single oral administration of Yahom may increase the regional cerebral blood flow under the effect of cerebral microvascular vasodilation.
- Published
- 2006
19. Effects of curcumin on tumor angiogenesis and biomarkers, COX-2 and VEGF, in hepatocellular carcinoma cell-implanted nude mice
- Author
-
Pornprom, Yoysungnoen, Porntip, Wirachwong, Pavaphon, Bhattarakosol, Hideyuki, Niimi, and Suthiluk, Patumraj
- Subjects
Vascular Endothelial Growth Factor A ,Carcinoma, Hepatocellular ,Curcumin ,Microscopy, Video ,Time Factors ,Neovascularization, Pathologic ,Membrane Proteins ,Angiogenesis Inhibitors ,Gene Expression Regulation, Neoplastic ,Mice ,Liver Neoplasms, Experimental ,Cyclooxygenase 2 ,Animals ,Biomarkers - Abstract
Anti-angiogenic activity of curcumin and effects of curcumin on angiogenic biomarkers, cycloxygenase (COX)-2 and vascular endothelial growth factor (VEGF) levels were investigated. One day after hepatocellular carcinoma cell (HepG2) cells (30 microl of 2 x 10(6) cells) were inoculated onto the upper layer of the skin-fold chamber (HepG2-group, n = 15), curcumin solutions of 300 and 3000 mg/kg BW were daily oral fed to HepG2-Cur-300 and HepG2-Cur-3000 groups (n = 30), respectively. Intravital fluorescence videomicroscopy was performed to monitor neocapillaries in the tumor on days 3, 7 and 14 post-tumor-inoculation, using RITC-dextran (0.1 ml of 0.5% injected intravenously). The tumor neocapillary density (NCD) was evaluated in correlation with the tumor area, using a digital image analysis. The results demonstrated that the NCD of HepG2-groups were significantly increased on day 7 and 14, compared to the aged-matched Sham-groups (p0.001). The increased NCD on day 7 and 14 were attenuated significantly by daily treatment of curcumin solution (3000 mg/kg BW).The curcumin treatment reduced the tumor-induced over-expression of COX-2 and serum VEGF in HepG2 groups significantly (p0.001), indicating that curcumin could inhibit tumor angiogenesis. This mechanism might be mediated through reduction of angiogenic biomarkers, COX-2 and VEGF.
- Published
- 2006
20. Asian traditional medicine (ATM): recent progress based on scientific evidences
- Author
-
Hideyuki, Niimi, Suthiluk, Patumraj, and Jing-Yan, Han
- Subjects
Medicine, East Asian Traditional ,Herbal Medicine ,Microcirculation ,Research ,Acupuncture Therapy ,Medicine, Kampo - Abstract
Asian traditional medicine (ATM) (herbal medicine, acupuncture or moxibution) has gained some popularity among communities in Asia. Some therapies employed in ATM have been verified using modern techniques, but the significance of ATM has still remained unclear. This symposium was focused on experimental data obtained recently.
- Published
- 2006
21. Microvascular hemodynamic responses to arteriovenous shunting in rat limb
- Author
-
Atushi, Nakano, Yutaka, Komai, Junji, Seki, Ricardo, Quintos, and Hideyuki, Niimi
- Subjects
Male ,Erythrocytes ,Microscopy, Video ,Microcirculation ,Hemodynamics ,Arterial Occlusive Diseases ,Extremities ,Transplantation, Autologous ,Capillaries ,Rats ,Veins ,Arteriovenous Shunt, Surgical ,Animals ,Rats, Wistar ,Blood Flow Velocity - Abstract
Autologus veins have been used clinically as a bypass conduit for reconstruction of small arteries, but there are few data available for microvascular response to arteriovenous (AV) shunting. This study was aimed to evaluate microvascular hemodynamic changes induced by creating AV anastomosis in rat hindlimb. Using intravital fluorescence videomicroscopy, we measured velocities of red blood cells (RBCs) flowing in the microvascular network in the control state, in the occlusion state where the superficial femoral artery (SFA) was occluded, and in the AV shunting state where the AV anastomosis was opened after occlusion of SFA. RBC velocities were measured in 155 capillaries of 6 rats using a dual window method and a frame-by-frame technique. The mean velocity and the coefficient of variation were 0.61 mm/sec and 0.90 in the control state, 0.34 mm/sec and 1.30 in the occlusion state, 0.83 mm/sec and 1.24 in the AV shunting state, respectively. These indicated that hemodynamic heterogeneity among capillaries increased with decrease in mean velocity following the arterial occlusion, while the AV shunting augmented the heterogeneity with increase in mean velocity. Capillaries with low perfusion (0.1 mm/sec) or high perfusion (1.0 mm/sec) were 5.8% or 20.6%, 29.6 or 5.2%, and 22.6 or 30.3% out of all measured capillaries in the control, occlusion and AV shunting conditions, respectively. In conclusion, AV shunting increased capillary perfusion and also its spatial heterogeneity, preferentially inducing high velocity in the microvasculature.
- Published
- 2005
22. Cell morphological changes in venous remodeling induced by arteriovenous grafting in rat limb
- Author
-
Yutaka, Komai, Atushi, Nakano, Junji, Seki, and Hideyuki, Niimi
- Subjects
Cell Nucleus ,Male ,Models, Anatomic ,Hyperplasia ,Microscopy, Confocal ,Phalloidine ,Endothelial Cells ,Femoral Vein ,Transplantation, Autologous ,Actins ,Muscle, Smooth, Vascular ,Rats ,Femoral Artery ,Arteriovenous Shunt, Surgical ,Lower Extremity ,Animals ,Blood Vessels ,Indicators and Reagents ,Ultrasonics ,Endothelium, Vascular ,Rats, Wistar ,Fluorescein-5-isothiocyanate ,Propidium - Abstract
Vascular remodeling induced in rat limb by arteriovenous (AV) shunting was investigated by evaluating changes in vascular diameter and cell morphology. In Wistar rats, a vein graft was implanted in situ in the hind limb. Flow-rate in the grafted vein was assessed by measuring flow in the common femoral artery using an ultrasonic flowmeter. Nuclei and actin filaments of the venous wall were stained with propidium iodine and phalloidine-FITC, and the samples were observed using confocal laser microscopy. The grafted veins became circular in cross-section with increase in diameter during two weeks after AV shunting. Owing to the increase in diameter, the estimated wall shear stress was not increased so much as the flow-rate. The confocal laser microscopic observation showed that endothelial cells (ECs) and smooth muscle cells (SMCs) in the grafted veins were either aligned well (2 out of 8 samples), or ECs were denudated and SMCs were disrupted (in 6 out of 8 samples). The cell density of ECs was unchanged from the control level. In conclusion, the grafted vein was remodeled with morphological changes in ECs and SMCs during 2 weeks after AV shunting.
- Published
- 2005
23. Capillary angiogenesis and remodeling induced in rat limb by arteriovenous shunting
- Author
-
Yutaka, Komai, Atushi, Nakano, and Hideyuki, Niimi
- Subjects
Male ,Microscopy, Confocal ,Time Factors ,Arteriovenous Anastomosis ,Microcirculation ,Neovascularization, Physiologic ,Models, Biological ,Capillaries ,Rats ,Arteriovenous Shunt, Surgical ,Lower Extremity ,Reperfusion ,Animals ,Rats, Wistar - Abstract
Capillary angiogenesis and remodeling induced by arteriovenous (AV) shunting in rat hind limb was investigated by evaluating changes in capillary density and diameter in the skeletal muscle subject to retrograde flow and high pressure. Wistar rats were used, and an AV anastomosis was created in the hind limb. Two weeks after AV shunting, the microvasculature in the limb was visualized by GS-lectine, and the samples were observed using confocal laser microscopy. The capillary density were increased by approximately 150% for small vessels (13 microm in diameter) under retrograde flow condition, but no change appeared for large vessels (13 microm in diameter). The capillary diameters were not significantly different between control and chronic condition. In conclusion, retrograde flow produced by AV shunting increased capillary density but it did not change the capillary diameter significantly.
- Published
- 2005
24. Cerebral angiogenesis induced by growth factors: intravital microscopic studies using models
- Author
-
Hideyuki, Niimi
- Subjects
Drug Implants ,Platelet-Derived Growth Factor ,Microscopy, Confocal ,Microscopy, Video ,Brain ,Neovascularization, Physiologic ,Receptors, Muscarinic ,Acetylcholine ,Capillaries ,Vasodilation ,Mice ,Microscopy, Fluorescence ,Models, Animal ,Animals ,Angiogenesis Inducing Agents ,Fibroblast Growth Factor 2 ,Pericytes ,Blood Flow Velocity - Abstract
Pharmacological induction of angiogenesis is a new treatment of cerebrovascular insufficiency without surgical treatment. It is an urgent task to investigate the dynamic process of angiogenesis and of the microvascular perfusion of the cerebral neoplastic tissue in vivo. The present study is concerned with microcirculatory aspects of cerebral neocapillaries in vivo. A novel model of cerebral angiogenesis was developed by inducing cerebral neocapillaries in mice using growth factors such as basic fibroblast growth factor (bFGF) and platelet-derived growth factor (PDGF). By a direct observation of the neocapillary microcirculation under a fluorescence videomicroscope, the neocapillary density, diameter and red cell velocity were measured to evaluate the development and remodeling of the neocapillaries with the number of days after incubation. The neocapillary response to topically applied acetylcholine (ACh) was examined by measuring changes in the diameter and red cell velocity. It was shown that PDGF-induced neocapillaries was dilated in response to ACh on day 28 after incubation, while bFGF-induced neocapillaries was not. Furthermore, the neocapillary pericytes were observed using confocal laser microscopy, based on the fluorescence immunohistochemical images of the neoplastic tissue. Several pericytes, stained with anti-NG_2, appeared in the neocapillaries. It was suggested that these pericytes might be recruited in the neocapillaries to regulate blood flow without vascular smooth muscle.
- Published
- 2004
25. Cerebral endothelial dysfunction in diabetes: intravital microscopic analysis using streptozotocin-induced diabetic rats
- Author
-
Amporn, Jariyapongskul, Suthiluk, Patumraj, and Hideyuki, Niimi
- Subjects
Male ,Microscopy, Video ,Microcirculation ,Vasodilator Agents ,Rats, Inbred WF ,Acetylcholine ,Streptozocin ,Diabetes Mellitus, Experimental ,Rats ,Vasodilation ,Arterioles ,Nitroglycerin ,Cerebrovascular Circulation ,Cell Adhesion ,Leukocytes ,Animals ,Vasoconstrictor Agents ,Endothelium, Vascular - Abstract
Endothelial function of cerebral microvessel in diabetes was evaluated using streptozotocin (STZ)-induced diabetic rats (blood glucose of/=300 mg/dl). At 36 weeks after STZ injection, the rats were anesthetized with sodium pentobarbital. The cerebral microcirculation in control and STZ groups was directly observed, using intravital fluorescence videomicroscopy. To evaluate the endothelial function in vivo, the number of leukocytes adhering to postcapillary venules were counted, and cerebral arteriolar responses to acetylcholine (ACh) and nitroglycerine (NTG) were examined. The results showed that the leukocyte adhesion to cerebral postcapillary venular endothelium increased significantly in STZ-rats, compared with control rats. The vasodilatory responses of cerebral arterioles (20-30 microm) to ACh decreased significantly in STZ-rats, compared with control rats (p0.01), but the responses to NTG did not alter in diabetes. These results indicate that the impaired responses should occur on the endothelial cell. In conclusion, endothelial dysfunction induced in diabetes are characterized by impaired endothelium-dependent vasodilation and increased leukocyte adhesion to endothelial cells.
- Published
- 2004
26. Asian traditional medicine (ATM) based on in vivo microcirculation evidence
- Author
-
Hideyuki, Niimi, Jing-Yan, Han, and Suthiluk, Patumraj
- Subjects
Medicine, East Asian Traditional ,Microcirculation ,Humans ,Holistic Health - Abstract
Asian traditional medicine (ATM) (herbal medicine, acupuncture or moxibution) has gained some popularity among communities in Asia, but there are still few evidences to prove the effectiveness of such therapeutic measures. A symposium was held with aim at the effectiveness of Asian traditional therapies in views of in vivo microcirculation. This report is concerned with the symposium, including Asian activities for ATM.
- Published
- 2004
27. Measurement of red cell velocity in microvessels using particle image velocimetry (PIV)
- Author
-
Atushi, Nakano, Yasuhiko, Sugii, Motomu, Minamiyama, and Hideyuki, Niimi
- Subjects
Male ,Arterioles ,Microscopy, Video ,Microcirculation ,Hemorheology ,Image Processing, Computer-Assisted ,Animals ,Splanchnic Circulation ,Rats, Wistar ,Blood Flow Velocity ,Rats - Abstract
A new technique using particle image velocimetry (PIV) has been developed to evaluate the detailed velocity profiles of red cells flowing in microvessels. The microcirculation in rat mesentery was directly observed using high-speed videomicroscopy, and the images of red cells flowing in the mesenteric arterioles were recorded simultaneously with the arterial blood pressure. Based on the high-speed videomicroscopic images obtained, velocity vectors in single or branched arterioles were evaluated to obtain velocity profiles across the cross-section of arterioles. It was shown that in single and straight arterioles the velocity profile was blunt with a pit at the central region, and its pit was marked in bifurcation. The present technique enables us to analyze red cell velocity profiles up to 0.8 microm in the spatial resolution and 1 msec in the time interval.
- Published
- 2004
28. Maturity of pericytes in cerebral neocapillaries induced by growth factors: fluorescence immuno-histochemical analysis using confocal laser microscopy
- Author
-
Amporn, Jariyapongskul, Atushi, Nakano, Saburo, Yamaguchi, Kolammal, Nageswari, and Hideyuki, Niimi
- Subjects
Cerebral Cortex ,Drug Implants ,Male ,Platelet-Derived Growth Factor ,Microscopy, Confocal ,Neovascularization, Physiologic ,Cell Differentiation ,Surgical Mesh ,Griffonia ,Capillaries ,Mice, Inbred C57BL ,Mice ,Microscopy, Fluorescence ,Animals ,Fibroblast Growth Factor 2 ,Proteoglycans ,Antigens ,Plant Lectins ,Fluorescent Antibody Technique, Indirect ,Pericytes - Abstract
The maturity of pericytes in cerebral neocapillaries induced by two different growth factors: basic fibroblast growth factor (bFGF) and platelet-derived growth factor (PDGF), was examined using an immunohistochemical staining technique. Cerebral angiogenesis was induced in mice by implanting a sandwich system of bFGF/PDGF gel and nylon-mesh over the exposed cortex. On 28th day after incubation, a small volume of cerebral tissue with the nylon-mesh was isolated and stained using tetramethyl rhodamine isothiocyanate (TRITC)-labeled secondary antibody to the primary antibody against NG_2 proteoglycan and fluorescein isothiocyanate (FITC)-labeled Griffonia simplicifolia (GS)-lectin. Using a confocal laser microscopic system, we observed the cerebral neocapillaries on the upper surface of the nylon-mesh and evaluated the maturity of pericytes stained with NG_2 based on the fluorescence immunohistological images. The pericyte appeared rich in neocapillaries induced by PDGF. It was suggested that pericytes might play a key role in the regulation of blood flow in neovessels.
- Published
- 2004
29. Cerebral microvascular responses to air embolism-reperfusion in the cat using fluorescence videomicroscopy
- Author
-
Saburo, Yamaguchi, Takashi, Yamakawa, and Hideyuki, Niimi
- Subjects
Male ,Disease Models, Animal ,Microscopy, Video ,Microscopy, Fluorescence ,Cerebrovascular Circulation ,Microcirculation ,Reperfusion ,Cats ,Animals ,Embolism, Air ,Female ,Fluorescent Dyes - Abstract
Cerebral microvascular changes due to air embolism-reperfusion in the cat were investigated. Air embolism-reperfusion was produced in the cerebral microvessels by an intra-carotid injection of air (0.2-0.3 ml). Air emboli in the cerebral arterioles were observed continuously from the air injection to reperfusion using fluorescence videomicroscopy. Arteriolar diameter was measured based on video images of arterioles filled with rhodamine-B isothiocyanate dextran, and red cell velocity was measured using a dual window technique with FITC-labeled red cells. Air bubbles ceased to move in the arterioles of 20-70 microm diameter and blood flow was almost stopped in distal arterioles. The air emboli were of cylindrical shape in the arterioles, with hemispherical end caps. The emboli progressed slowly at rates of 7-73 microm/sec and then flowed away. The air emboli induced ischemia-reperfusion with the ischemic duration of approximately 1 minute (10 sec-3 min) at the arteriolar level. Cerebral arterioles began to dilate after the formation of the air emboli and significantly dilated by approximately 50% after reperfusion. A transient increase in red cell velocity was observed after reperfusion. Arteriolar dilation and the increase in velocity led to a hyperemic response in arteriolar flow to ischemia-reperfusion.
- Published
- 2003
30. The effect of long-term supplementation of vitamin C on leukocyte adhesion to the cerebral endothelium in STZ-induced diabetic rats
- Author
-
Amporn, Jariyapongskul, Suthiluk, Patumraj, Saburo, Yamaguchi, and Hideyuki, Niimi
- Subjects
Microscopy, Video ,Microcirculation ,Brain ,Ascorbic Acid ,Streptozocin ,Diabetes Mellitus, Experimental ,Rats ,Cerebrovascular Circulation ,Dietary Supplements ,Cell Adhesion ,Leukocytes ,Animals ,Endothelium, Vascular ,Rats, Wistar - Abstract
The effect of long-term supplementation of vitamin C on leukocyte adhesion to the cerebral endothelium was investigated in streptozotocin (STZ)-induced diabetic rats. Diabetes was induced in male Wistar Furth rats by intravenous injection of STZ. The vitamin C, ascorbic acid, was supplemented with drinking water (1 g/l). The rats were divided into control and diabetic groups without or with supplementation of vitamin C. The cerebral microcirculation was directly observed through a cranial window after different periods (12, 24 and 36 weeks) of vitamin C supplementation, using fluorescence videomicroscopy. Leukocyte adhesion to the venular endothelium was examined by labeling leukocytes with rhodamin 6G. The number density of adherent leukocytes in STZ-diabetic rats was increased significantly, compared with control rats. This increase in leukocyte adhesion was prevented by the long-term supplemented vitamin C. It was suggested that the antioxidant effect of vitamin C might be responsible for the prevention of leukocyte adhesion in diabetes mellitus.
- Published
- 2002
31. Cerebral microcirculatory changes in rat with a cardiopulmonary bypass using fluorescence videomicroscopy
- Author
-
Yoshihiko, Ohnishi, Qing-Hua, Hu, Saburo, Yamaguchi, Masakazu, Kuro, and Hideyuki, Niimi
- Subjects
Male ,Cardiopulmonary Bypass ,Microscopy, Video ,Microcirculation ,Partial Pressure ,Models, Cardiovascular ,Blood Pressure ,Carbon Dioxide ,Cerebral Arteries ,Rats ,Oxygen ,Arterioles ,Microscopy, Fluorescence ,Heart Rate ,Cerebrovascular Circulation ,Animals ,Rats, Wistar - Abstract
Cerebral microcirculatory changes in rat with a cardiopulmonary bypass (CPB) at normothermia was investigated in relation to cerebrovascular disorders caused by surgical operation with CPB. The mean arterial pressure was changed from 50 to 200 mmHg by changing the pump flow-rate. A non-pulsatile flow model was developed by stopping the cardiac beat using a fibrillator. The pial microcirculation was visualized using fluorescence-labeled red cells and dextran, and was directly observed under a fluorescence videomicroscope during CPB. Based on the recorded videoimages, the arteriolar diameter and red cell velocity were measured, in which single arterioles with approximately 40 microm diameter were selected among the pial arterioles. It was shown that when the arterial pressure was changed: (1) arteriolar vasodilation or constriction appeared during pulsatile flow but it disappeared during non-pulsatile flow, and (2) the arteriolar red cell velocity increased or decreased linearly during non-pulsatile flow as well as pulsatile flow. The flow-rate was almost constant at a large range of the mean arterial pressure from 60 to 160 mmHg during pulsatile flow (autoregulation), but it increased or decreased during non-pulsatile flow with an increase or decrease in mean arterial pressure, respectively. It was suggested that pulsativity might be responsible for cerebral autoregulation.
- Published
- 2002
32. Numerical Simulation of Co-operative Regulation in the Cerebral Microvascular Arcadal Network
- Author
-
Yutaka Komai, Hideyuki Niimi, and Saburo Yamaguchi
- Subjects
Co operative ,Microvascular Network ,Materials science ,Computer simulation ,medicine.diagnostic_test ,Flow regulation ,medicine ,Hemodynamics ,Hematocrit ,circulatory and respiratory physiology ,Biomedical engineering - Abstract
Biomathematical models for cat cerebral arteriolar network were developed for numerical evaluation of the significance of arcadal structure in the cerebral microvascular hemodynamics. Heterogeneous distribution of hematocrit and mutual co-operation in the flow regulation in the arcadal network were demonstrated using the numerical simulation.
- Published
- 2000
- Full Text
- View/download PDF
33. Blood flow Velocity Profile in Rat Mesenteric Arterioles using Micro PIV : Comparison at Branch and Confluence
- Author
-
Yasuhiko Sugii, Hideyuki Niimi, Motomu Minamiyama, Atushi Nakano, and Shigeru Nishio
- Subjects
Materials science ,Confluence ,Blood flow ,Biomedical engineering - Published
- 2003
- Full Text
- View/download PDF
34. Microscopic Visualization of Flow in Rat Cerebral Arteries: Biofluid Dynamical Study on Experimentally Induced Aneurysm
- Author
-
Haruhiko Kikuchi, Hideyuki Niimi, Nobuo Hashimoto, Hideyuki Nakatani, and Saburo Yamaguchi
- Subjects
Pathology ,medicine.medical_specialty ,Chemistry ,Cerebral arteries ,Hemodynamics ,Anatomy ,medicine.disease ,Latex particle ,Apex (geometry) ,Microscopic observation ,Endothelial stem cell ,Aneurysm ,medicine.artery ,cardiovascular system ,medicine ,Anterior cerebral artery ,sense organs ,skin and connective tissue diseases - Abstract
Hemodynamic force may be an important factor to develop cerebral aneurysm since its early change often occurs at the cerebral artery bifurcation [1]. In previous studies [2,3], we proved that a cerebral aneurysm could be induced successfully in rats. The scanning electron microscopic observation on the aneurysm showed early changes of the endothelial cell just distal to the apex of the cerebral artery bifurcation [4]. This suggested that the endothelial change might be closely connected with flow near the apex [3].
- Published
- 1990
- Full Text
- View/download PDF
35. Hematocrit dependence of cell-free layer thickness in cat cerebral arterioles: an intravital fluorescence microscopic observation
- Author
-
M.A. Hussain, T. Yamakawa, and Hideyuki Niimi
- Subjects
Materials science ,Nuclear magnetic resonance ,medicine.diagnostic_test ,Physiology ,Physiology (medical) ,medicine ,Analytical chemistry ,Cell free ,Hematocrit ,Fluorescence ,Layer thickness ,Microscopic observation - Published
- 1996
- Full Text
- View/download PDF
36. Hemodynamic changes in cerebral microcirculation of cat under halothaneanesthesia: An intravital fluorescence video-microscopic study
- Author
-
M.A. Hussain, T. Nakaiima, M. Kuro, Hideyuki Niimi, and S. Yamagchi
- Subjects
Pathology ,medicine.medical_specialty ,Physiology ,business.industry ,Physiology (medical) ,Medicine ,Hemodynamics ,Cerebral microcirculation ,business ,Fluorescence - Published
- 1996
- Full Text
- View/download PDF
37. HEMODYNAMIC CHANGE IN CEREBRAL MICROVASCULAR NETWORK OF CAT IN HALOTHANE-INDUCED HYPOTENSION
- Author
-
Md. Asif Hussain, Masakazu Kuro, Hideyuki Niimi, Toshito Nakajima, and Saburo Yamaguchi
- Subjects
Microvascular Network ,business.industry ,Anesthesia ,Emergency Medicine ,Medicine ,Hemodynamics ,Halothane ,Critical Care and Intensive Care Medicine ,business ,Induced Hypotension ,medicine.drug - Published
- 1995
- Full Text
- View/download PDF
38. Cerebral angiogenesis induced by growth factors: intravital microscopic studies using models.
- Author
-
Hideyuki Niimi, Bob
- Subjects
- *
NEOVASCULARIZATION , *CEREBRAL arterial diseases , *BLOOD flow , *VASCULAR smooth muscle , *MICROCIRCULATION , *BLOOD circulation - Abstract
Pharmacological induction of angiogenesis is a new treatment of cerebrovascular insufficiency without surgical treatment. It is an urgent task to investigate the dynamic process of angiogenesis and of the microvascular perfusion of the cerebral neoplastic tissue in vivo. The present study is concerned with microcirculatory aspects of cerebral neocapillaries in vivo. A novel model of cerebral angiogenesis was developed by inducing cerebral neocapillaries in mice using growth factors such as basic fibroblast growth factor (bFGF) and platelet‐derived growth factor (PDGF). By a direct observation of the neocapillary microcirculation under a fluorescence videomicroscope, the neocapillary density, diameter and red cell velocity were measured to evaluate the development and remodeling of the neocapillaries with the number of days after incubation. The neocapillary response to topically applied acetylcholine (ACh) was examined by measuring changes in the diameter and red cell velocity. It was shown that PDGF‐induced neocapillaries was dilated in response to ACh on day 28 after incubation, while bFGF‐induced neocapillaries was not. Furthermore, the neocapillary pericytes were observed using confocal laser microscopy, based on the fluorescence immunohistochemical images of the neoplastic tissue. Several pericytes, stained with anti‐NG[sub 2] , appeared in the neocapillaries. It was suggested that these pericytes might be recruited in the neocapillaries to regulate blood flow without vascular smooth muscle. [ABSTRACT FROM AUTHOR]
- Published
- 2003
39. Asian traditional medicine (ATM) based on in vivo microcirculation evidence.
- Author
-
Hideyuki Niimi, Bob, Jing-yan Han, Bob, and Suthiluk Patumraj, Bob
- Subjects
- *
HERBAL medicine , *TRADITIONAL medicine , *ALTERNATIVE medicine , *MICROCIRCULATION , *BLOOD circulation , *ACUPUNCTURE - Abstract
Asian traditional medicine (ATM) (herbal medicine, acupuncture or moxibution) has gained some popularity among communities in Asia, but there are still few evidences to prove the effectiveness of such therapeutic measures. A symposium was held with aim at the effectiveness of Asian traditional therapies in views of in vivo microcirculation. This report is concerned with the symposium, including Asian activities for ATM. [ABSTRACT FROM AUTHOR]
- Published
- 2003
40. Cerebral endothelial dysfunction in diabetes: intravital microscopic analysis using streptozotocin‐induced diabetic rats.
- Author
-
Amporn Jariyapongskul, Bob, Suthiluk Patumraj, Bob, and Hideyuki Niimi, Bob
- Subjects
ENDOTHELIUM ,CEREBRAL circulation ,DIABETES ,STREPTOZOTOCIN ,LEUCOCYTES ,ACETYLCHOLINE - Abstract
Endothelial function of cerebral microvessel in diabetes was evaluated using streptozotocin (STZ)‐induced diabetic rats (blood glucose of ≥300 mg/dl). At 36 weeks after STZ injection, the rats were anesthetized with sodium pentobarbital. The cerebral microcirculation in control and STZ groups was directly observed, using intravital fluorescence videomicroscopy. To evaluate the endothelial function in vivo, the number of leukocytes adhering to postcapillary venules were counted, and cerebral arteriolar responses to acetylcholine (ACh) and nitroglycerine (NTG) were examined. The results showed that the leukocyte adhesion to cerebral postcapillary venular endothelium increased significantly in STZ‐rats, compared with control rats. The vasodilatory responses of cerebral arterioles (20–30 μm) to ACh decreased significantly in STZ‐rats, compared with control rats (p<0.01), but the responses to NTG did not alter in diabetes. These results indicate that the impaired responses should occur on the endothelial cell. In conclusion, endothelial dysfunction induced in diabetes are characterized by impaired endothelium‐dependent vasodilation and increased leukocyte adhesion to endothelial cells. [ABSTRACT FROM AUTHOR]
- Published
- 2003
41. Maturity of pericytes in cerebral neocapillaries induced by growth factors: fluorescence immuno‐histochemical analysis using confocal laser microscopy.
- Author
-
Amporn Jariyapongskul, Bob, Atushi Nakano, Bob, Saburo Yamaguchi, Bob, Kolammal Nageswari, Bob, and Hideyuki Niimi, Bob
- Subjects
CEREBRAL veins ,FIBROBLAST growth factors ,PROTEOGLYCANS ,PLATELET-derived growth factor ,NEOVASCULARIZATION ,CAPILLARIES ,BLOOD flow - Abstract
The maturity of pericytes in cerebral neocapillaries induced by two different growth factors: basic fibroblast growth factor (bFGF) and platelet‐derived growth factor (PDGF), was examined using an immunohistochemical staining technique. Cerebral angiogenesis was induced in mice by implanting a sandwich system of bFGF/PDGF gel and nylon‐mesh over the exposed cortex. On 28th day after incubation, a small volume of cerebral tissue with the nylon‐mesh was isolated and stained using tetramethyl rhodamine isothiocyanate (TRITC)‐labeled secondary antibody to the primary antibody against NG[sub 2] proteoglycan and fluorescein isothiocyanate (FITC)‐labeled Griffonia simplicifolia (GS)‐lectin. Using a confocal laser microscopic system, we observed the cerebral neocapillaries on the upper surface of the nylon‐mesh and evaluated the maturity of pericytes stained with NG[sub 2] based on the fluorescence immunohistological images. The pericyte appeared rich in neocapillaries induced by PDGF. It was suggested that pericytes might play a key role in the regulation of blood flow in neovessels. [ABSTRACT FROM AUTHOR]
- Published
- 2003
42. Measurement of red cell velocity in microvessels using particle image velocimetry (PIV).
- Author
-
Atushi Nakano, Bob, Yasuhiko Sugii, Bob, Motomu Minamiyama, Bob, and Hideyuki Niimi, Bob
- Subjects
PARTICLE image velocimetry ,ERYTHROCYTES ,MICROCIRCULATION ,MESENTERY ,BLOOD pressure ,LABORATORY rats - Abstract
A new technique using particle image velocimetry (PIV) has been developed to evaluate the detailed velocity profiles of red cells flowing in microvessels. The microcirculation in rat mesentery was directly observed using high‐speed videomicroscopy, and the images of red cells flowing in the mesenteric arterioles were recorded simultaneously with the arterial blood pressure. Based on the high‐speed videomicroscopic images obtained, velocity vectors in single or branched arterioles were evaluated to obtain velocity profiles across the cross‐section of arterioles. It was shown that in single and straight arterioles the velocity profile was blunt with a pit at the central region, and its pit was marked in bifurcation. The present technique enables us to analyze red cell velocity profiles up to 0.8 μm in the spatial resolution and 1 msec in the time interval. [ABSTRACT FROM AUTHOR]
- Published
- 2003
43. Role of stress concentration in arterial walls in atherogenesis1
- Author
-
Hideyuki Niimi
- Subjects
Physiology ,Chemistry ,Physiology (medical) ,Biophysics ,Stress concentration - Published
- 1979
- Full Text
- View/download PDF
44. Multi-Phase Flow Model of Blood Flow
- Author
-
Hideyuki Niimi
- Subjects
Flow (mathematics) ,Chemistry ,Multiphase flow ,Newtonian fluid ,Analytical chemistry ,Hemorheology ,Blood flow ,Data flow model ,Microvessel ,Biomedical engineering ,Suspension (chemistry) - Abstract
Blood is a suspension of blood cells in a Newtonian fluid of plasma. The red blood cells (RBCs) are most numerous and behave like small deformable capsules containing a Newtonian fluid. How to treat blood flowing through vessels depends on the scale involved. The flow characteristics of blood in the microvessel with a diameter comparable with the RBC size may be determined by the behavior of individual RBCs, for which a multi-phase flow model may provide a good approximation. Some multiphase flow problems of blood flow are studied.
- Published
- 1987
- Full Text
- View/download PDF
45. PLASMA FLOW INDUCED BY ERYTHROCYTE SEDIMENTATION IN INCLINED TUBES
- Author
-
Saburo Yamaguchi and Hideyuki Niimi
- Subjects
Gravity (chemistry) ,Materials science ,business.industry ,Sedimentation (water treatment) ,Suspension (chemistry) ,Plasma flow ,chemistry.chemical_compound ,Optics ,chemistry ,Settling ,Tube (fluid conveyance) ,Polystyrene ,Composite material ,business ,Layer (electronics) - Abstract
It has been recognized since Boycott (1920) that erythrocyte sedimentation rate is significantly increased in inclined tubes. To fully understand the enhanced settling process, microscopic observation was made of the motion of erythrocyte-Ringer suspension under gravity settling in two inclined tubes (straight and kinked). Polystyrene particles of approximately 1 μm diameter were put into the suspension to visualize the motion of the fluid (Ringer solution) under microscope-TV camera.A thin layer of cell-free fluid was observed underneath the downward-facing surface of the two tubes, in which strong up-flow was induced. The sedimentation rate and the thickness of the cell-free layer were measured for angles of inclination in the straight tube. Both of them were increased with Increase in tube inclination up to 45 degree. This strongly suggests that the enhanced sedimentation rate may be closely connected with the cell-free layer near the inclined wall. The inclined settling process was discussed from a stand-point of two-phase fluid-dynamics.
- Published
- 1985
- Full Text
- View/download PDF
46. Structure of blood flow through a curved vessel with an aneurysm
- Author
-
Hideyuki Niimi, Ikuo Sugiyama, and Yosuke Kawano
- Subjects
Flow visualization ,Materials science ,Physiology ,Models, Cardiovascular ,Intracranial Aneurysm ,Blood flow ,medicine.disease ,Secondary flow ,Thrombosis ,Vortex ,Cerebral circulation ,Aneurysm ,Flow (mathematics) ,Regional Blood Flow ,Physiology (medical) ,cardiovascular system ,medicine ,Humans ,Rheology ,Blood Flow Velocity ,Biomedical engineering - Abstract
A fine structure of blood flow through a curved vessel with an aneurysm was studied in in vitro experiments in relation to rheological factors of arterial diseases such as arteriosclerosis or thrombosis. On the basis of the in vivo data related to cerebral circulation, red blood cell suspension was flowed through curved vessel models with an asymmetrical aneurysm. Flow visualization was made with a microscope 16 mm cinecamera-TV monitor system, and the velocity profile was measured using the laser Doppler velocimeter. Vortices induced in aneurysm influenced flow structure and velocity at the presence of the secondary flow due to the vessel curvature. This suggests strongly that blood flow in curved arteries with an aneurysm must be understood under the influence of the secondary flow.
- Published
- 1984
- Full Text
- View/download PDF
47. Nonlinear Theory of Pulse Waves in Blood Vessels
- Author
-
Atsushi Okumura, Kouzo Moritake, Kozaburo Hayashi, Masaaki Sato, Hajime Handa, and Hideyuki Niimi
- Subjects
Physics ,Quantitative Biology::Tissues and Organs ,Nonlinear theory ,Mathematics::Analysis of PDEs ,Rotational symmetry ,General Physics and Astronomy ,Quantitative Biology::Cell Behavior ,Pulse (physics) ,Physics::Fluid Dynamics ,Nonlinear system ,Classical mechanics ,Modulation ,Homogeneous ,Compressibility ,Tube (fluid conveyance) - Abstract
The theory of nonlinear pulse waves due to nonlinearity of vascular walls is established. The blood is supposed to behave as an incompressible and homogeneous fluid obeying the Navier-Stokes equation, while the blood vessel is assumed to be a long axisymmetric tube whose mechanical properties are prescribed experimentally. The problem of the modulation of pressure waves is investigated.
- Published
- 1975
- Full Text
- View/download PDF
48. Effect of high osmotic media on blood viscosity and red blood cell deformability
- Author
-
Hideyuki Niimi and Akemi Yamamoto
- Subjects
Erythrocytes ,Physiology ,Blood viscosity ,Diatrizoate ,Osmolar Concentration ,Viscosity ,Dogs ,Osmotic Pressure ,Physiology (medical) ,medicine ,Animals ,Osmotic pressure ,Diatrizoate Meglumine ,Chemistry ,hemic and immune systems ,Blood flow ,Blood Viscosity ,Plasma osmolality ,Red blood cell ,medicine.anatomical_structure ,Immunology ,Biophysics ,Hemorheology ,Rheology ,circulatory and respiratory physiology - Abstract
Effects of high osmotic media on the shape and deformability of RBC were examined for determining increasing factors of blood viscosity. Dog blood and Urographin (a hypertonic contrast medium) were used; the plasma osmolality was changed by Urografin suspended in blood. The viscosity was measured for normal RBC and glutaraldehyde-treated RBC suspensions with a cell volume concentration. The RBC deformability was evaluated from the difference in viscosity between the two suspensions. It was shown that normal RBC suspension increased the viscosity with increase in osmolality at high shear rate; hardened RBC suspension decreased the viscosity with increase in osmolality. It was concluded that the RBC deformability decreased with increasing osmolality.
- Published
- 1983
- Full Text
- View/download PDF
49. Developing pulsatile flow in a curved pipe
- Author
-
Yosuke Kawano, Hideyuki Niimi, and Ikuo Sugiyama
- Subjects
Mechanical Engineering ,Pulsatile flow ,Mechanics ,Condensed Matter Physics ,Geology - Abstract
曲管内の拍動流における断面内速度分布をレーザ流速計を用いて測定し,その流速パターンが湾曲に沿ってどのように推移するかを実験的に調べた.速度分布は,湾曲および拍動の両者の影響を受け,特に最大流速が外側壁に移動した非対称な速度分布を示す時間位相と,ほぼ一様な速度分布を示す時間位相が存在することを明らかにした.管壁近傍の流速分布を基に,壁ずり速度を評価し,その場所的推移を調べた.
- Published
- 1985
- Full Text
- View/download PDF
50. [Untitled]
- Author
-
Yosuke KAWANO, Ikuo SUGIYAMA, and Hideyuki NIIMI
- Published
- 1984
- Full Text
- View/download PDF
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.