81 research outputs found

    A MATHEMATICAL THEORY FOR BLOOD FLOW DYNAMICS IN THE ARTERIAL SYSTEM analysis of rotation angle and dynamical equations for forces and moments operating on artreial wall.

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    We have established a mathematical model of arterial system. This paper expand theoretical analysis of the mechanical dynamical structure of the arterial wall. The general deformation theory of dynamical analysis was applied to establish the balancing equations of the forces and moments that operate on the arterial wall surface. To generalyze the dynamical problem,we brought the shell theory of the curved surface into the analysis of the arterial wall surface. To associate and identify the directions of the forces and moments before and after the deformation, we firstly analyzed the relative rotation angles between each lines of the micro surface elements around the 3 axies which were founded on the elements. Utilyzing these parameters of the relative rotation, movements, we induced the balancing equations of the forces. Since we Assume more general case, we also studied the balancing equations of bending,twisting moments and transverse shear. Then we have obtained 6 equilibrium equation in 3 directions. This paper is one of the vital points of the mathematical expansion of our theory. [The constructive dynamic analysis of the arterial wall] -1 The rotation angle of the arterial wall and the equilibrium equations for the stress and moments operating on the wall

    A MATHEMATICAL THEORY FOR BLOOD FLOW DYNAMICS IN THE ARTERIAL SYSTEM an induction of blood flow velocity.

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    A theoretical expansion of mathematical models of the cardiovascular system is developed. We established a distributed parameter model of the arterial system. In this paper we have deduced the blood flow velocities in the longitudinal and radical direction based mainly on the Womersley theory. Neglecting the non-liner terms (the convective acceleration terms) in the Navier-Stokes equation and setting linear cyclic solutions, the N-S equations were reduced to the Bessel type ordinary differential equations. By utilizing the Strokes stream function, the equation which input pressure satisfy was proved to be a Bessel type differential equation. Applying the Bessel type pressure function to the linearlyzed N-S equation, a strict form of the solution of the blood flow velocities was obtained. These solutions were confirmed to satisfy the conservative law of mass. To ensure whether these solutions satisfy the Strokes stream function another process was used to obtain the blood flow velocities. Turning to the stream function and differentiating directly of these functions also induced a series of solutions which are identical with the solutions that were obtained by solving the Bessel type N-S equation. By these strict mathematical processes, linear solutions of the blood flow velocities were obtained. To simplify the system and problems we made some assumptions and we have discussed the validity of these assumptions within the range we concern

    Effect of Keishibukuryogan, a Japanese Traditional Kampo Prescription, on Improvement of Microcirculation and Oketsu and Induction of Endothelial Nitric Oxide: A Live Imaging Study

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    Oketsu is a characteristic condition that plays an important role in Kampo, Japanese traditional medicine, and includes multiple aspects of hemodynamic disorders. This study aims to clarify the microcirculation of Oketsu and the pharmacological effect of Keishibukuryogan, an anti-Oketsu Kampo prescription, using live imaging techniques. Oral administration of Keishibukuryogan induced significant vasodilation of murine subcutaneous arterioles compared to the preadministration level. This vasodilatation peaked 60 min after administration and persisted for 90 min. The blood velocity in the subcutaneous capillary was also increased by Keishibukuryogan in generally the same manner. In rat mesenteric arterioles, Keishibukuryogan administration improved microhemodynamic parameters, including the resolution of erythrocyte congestion and the cell-free layer, which are representative of Oketsu pathology. Live imaging revealed an increase of diaminofluorescein-2 diacetate fluorescence, a nitric oxide (NO) specific reagent, in the arterial endothelium following Keishibukuryogan administration. This fluorescence was most remarkable at vascular bifurcations but was present throughout the mesenteric arterioles. This study demonstrates the successful imaging of Oketsu pathology with respect to microcirculation and the anti-Oketsu effects of Keishibukuryogan, namely, vasodilation of arterioles, increased blood velocity, and resolution of erythrocyte congestion. The anti-Oketsu effect of Keishibukuryogan is related to endothelial NO production

    Contractile Properties of Esophageal Striated Muscle: Comparison with Cardiac and Skeletal Muscles in Rats

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    The external muscle layer of the mammalian esophagus consists of striated muscles. We investigated the contractile properties of esophageal striated muscle by comparison with those of skeletal and cardiac muscles. Electrical field stimulation with single pulses evoked twitch-like contractile responses in esophageal muscle, similar to those in skeletal muscle in duration and similar to those in cardiac muscle in amplitude. The contractions of esophageal muscle were not affected by an inhibitor of gap junctions. Contractile responses induced by high potassium or caffeine in esophageal muscle were analogous to those in skeletal muscle. High-frequency stimulation induced a transient summation of contractions followed by sustained contractions with amplitudes similar to those of twitch-like contractions, although a large summation was observed in skeletal muscle. The results demonstrate that esophageal muscle has properties similar but not identical to those of skeletal muscle and that some specific properties may be beneficial for esophageal peristalsis

    Effect of Keishibukuryogan, a Japanese Traditional Kampo Prescription, on Improvement of Microcirculation and Oketsu and Induction of Endothelial Nitric Oxide: A Live Imaging Study

    Get PDF
    Oketsu is a characteristic condition that plays an important role in Kampo, Japanese traditional medicine, and includes multiple aspects of hemodynamic disorders. This study aims to clarify the microcirculation of Oketsu and the pharmacological effect of Keishibukuryogan, an anti-Oketsu Kampo prescription, using live imaging techniques. Oral administration of Keishibukuryogan induced significant vasodilation of murine subcutaneous arterioles compared to the preadministration level. This vasodilatation peaked 60 min after administration and persisted for 90 min. The blood velocity in the subcutaneous capillary was also increased by Keishibukuryogan in generally the same manner. In rat mesenteric arterioles, Keishibukuryogan administration improved microhemodynamic parameters, including the resolution of erythrocyte congestion and the cell-free layer, which are representative of Oketsu pathology. Live imaging revealed an increase of diaminofluorescein-2 diacetate fluorescence, a nitric oxide (NO) specific reagent, in the arterial endothelium following Keishibukuryogan administration. This fluorescence was most remarkable at vascular bifurcations but was present throughout the mesenteric arterioles. This study demonstrates the successful imaging of Oketsu pathology with respect to microcirculation and the anti-Oketsu effects of Keishibukuryogan, namely, vasodilation of arterioles, increased blood velocity, and resolution of erythrocyte congestion. The anti-Oketsu effect of Keishibukuryogan is related to endothelial NO production

    Lansoprazole inhibits mitochondrial superoxide production and cellular lipid peroxidation induced by indomethacin in RGM1 cells

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    Lansoprazole is effective in healing non-steroidal anti-inflammatory drugs induced ulcers, and antioxidant properties have been thought to play a key role in healing ulcers. We hypothesize that lansoprazole exerts a cytoprotective effect by inhibiting reactive oxygen species leakage from mitochondria and lipid peroxidation. We pretreated gastric epithelial RGM1 cells with lansoprazole and then treated them with indomethacin in vitro. We found that the lansoprazole pretreatment significantly reduced cellular injury, maintained mitochondrial transmembrane potential, and decreased lipid peroxidation. Furthermore, the signal intensity of the electron spin resonance spectrum of the indomethacin-treated mitochondria which were pretreated with lansoprazole showed considerable reduction compared to those without the lansoprazole pretreatment. These results suggest that lansoprazole reduced superoxide production in the mitochondria of indomethacin treated cells, and subsequently inhibited lipid peroxide and cellular injury in gastric epithelial cells

    Pcdhβ deficiency affects hippocampal CA1 ensemble activity and contextual fear discrimination

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    Clustered protocadherins (Pcdhs), a large group of adhesion molecules, are important for axonal projections and dendritic spread, but little is known about how they influence neuronal activity. The Pcdhβ cluster is strongly expressed in the hippocampus, and in vivo Ca2+ imaging in Pcdhβ-deficient mice revealed altered activity of neuronal ensembles but not of individual cells in this region in freely moving animals. Specifically, Pcdhβ deficiency increased the number of large-size neuronal ensembles and the proportion of cells shared between ensembles. Furthermore, Pcdhβ-deficient mice exhibited reduced repetitive neuronal population activity during exploration of a novel context and were less able to discriminate contexts in a contextual fear conditioning paradigm. These results suggest that one function of Pcdhβs is to modulate neural ensemble activity in the hippocampus to promote context discrimination

    Iron accumulation causes impaired myogenesis correlated with MAPK signaling pathway inhibition by oxidative stress

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    Skeletal muscle atrophy is caused by disruption in the homeostatic balance of muscle degeneration and regeneration under various pathophysiological conditions. We have previously reported that iron accumulation induces skeletal muscle atrophy via a ubiquitin ligase-dependent pathway. However, the potential effect of iron accumulation on muscle regeneration remains unclear. To examine the effect of iron accumulation on myogenesis, we used a mouse model with cardiotoxin (CTX)-induced muscle regeneration in vivo and C2C12 mice myoblast cells in vitro. In mice with iron overload, the skeletal muscles exhibited increased oxidative stress and decreased expression of satellite cell markers. Following CTX-induced muscle injury, these mice also displayed delayed muscle regeneration with a decrease in the size of regenerating myofibers, reduced expression of myoblast differentiation markers, and decreased phosphorylation of mitogen-activated protein kinase signaling pathways. In vitro, iron overload also suppressed the differentiation of C2C12 myoblast cells, but the suppression could be reversed by superoxide scavenging using tempol. Excess iron inhibits myogenesis via oxidative stress, leading to an imbalance in skeletal muscle homeostasis

    Effect of Saxagliptin on Endothelial Function in Patients with Type 2 Diabetes : A Prospective Multicenter Study

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    The dipeptidyl peptidase-4 inhibitor saxagliptin is a widely used antihyperglycemic agent in patients with type 2 diabetes. The purpose of this study was to evaluate the effects of saxagliptin on endothelial function in patients with type 2 diabetes. This was a prospective, multicenter, interventional study. A total of 34 patients with type 2 diabetes were enrolled at four university hospitals in Japan. Treatment of patients was initially started with saxagliptin at a dose of 5 mg daily. Assessment of endothelial function assessed by flow-mediated vasodilation (FMD) and measurement of stromal cell-derived factor-1α (SDF-1α) were conducted at baseline and at 3 months after treatment with saxagliptin. A total of 31 patients with type 2 diabetes were included in the analysis. Saxagliptin significantly increased FMD from 3.1 ± 3.1% to 4.2 ± 2.4% (P = 0.032) and significantly decreased total cholesterol from 190 ± 24 mg/dL to 181 ± 25 mg/dL (P = 0.002), glucose from 160 ± 53 mg/dL to 133 ± 25 mg/dL (P < 0.001), HbA1c from 7.5 ± 0.6% to 7.0 ± 0.6% (P < 0.001), urine albumin-to-creatinine ratio from 63.8 ± 134.2 mg/g to 40.9 ± 83.0 mg/g (P = 0.043), and total SDF-1α from 2108 ± 243 pg/mL to 1284 ± 345 pg/mL (P < 0.001). These findings suggest that saxagliptin is effective for improving endothelial function

    Inhibitory action of iron on erythropoietin via oxidative stress-HIF-2α pathway

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    Renal anemia is a major complication in chronic kidney disease (CKD). Iron supplementation, as well as erythropoiesis-stimulating agents, are widely used for treatment of renal anemia. However, excess iron causes oxidative stress via the Fenton reaction, and iron supplementation might damage remnant renal function including erythropoietin (EPO) production in CKD. EPO gene expression was suppressed in mice following direct iron treatment. Hypoxia-inducible factor-2 alpha (HIF-2α), a positive regulator of the EPO gene, was also diminished in the kidney of mice following iron treatment. Anemia-induced increase in EPO and HIF-2α expression was also inhibited by iron-treatment. In in vitro experiments using EPO-producing HepG2 cells, iron stimulation reduced the expression of the EPO gene, as well as HIF-2α. Moreover, iron treatment augmented oxidative stress, and iron-induced reduction of EPO and HIF-2α expression was restored by tempol, an anti-oxidant compound. HIF-2α interaction with the EPO promoter was inhibited by iron treatment, and was restored by tempol. These findings suggested that iron supplementation reduced EPO gene expression via an oxidative stress-HIF-2α-dependent signaling pathway
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