29 results on '"Takata, Masao"'
Search Results
2. CCR2 mediates the adverse effects of LPS in the pregnant mouse.
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Hua, Renyi, Edey, Lydia F, O'Dea, Kieran P, Howe, Laura, Herbert, Bronwen R, Cheng, Weiwei, Zheng, Xia, MacIntyre, David A, Bennett, Philip R, Takata, Masao, and Johnson, Mark R
- Abstract
In our earlier work, we found that intrauterine (i.u.) and intraperitoneal (i.p.) injection of LPS (10-μg serotype 0111:B4) induced preterm labor (PTL) with high pup mortality, marked systemic inflammatory response and hypotension. Here, we used both i.u. and i.p. LPS models in pregnant wild-type (wt) and CCR2 knockout (CCR2-/-) mice on E16 to investigate the role played by the CCL2/CCR2 system in the response to LPS. Basally, lower numbers of monocytes and macrophages and higher numbers of neutrophils were found in the myometrium, placenta, and blood of CCR2-/- vs. wt mice. After i.u. LPS, parturition occurred at 14 h in both groups of mice. At 7 h post-injection, 70% of wt pups were dead vs. 10% of CCR2-/- pups, but at delivery 100% of wt and 90% of CCR2-/- pups were dead. Myometrial and placental monocytes and macrophages were generally lower in CCR2-/- mice, but this was less consistent in the circulation, lung, and liver. At 7 h post-LPS, myometrial ERK activation was greater and JNK and p65 lower and the mRNA levels of chemokines were higher and of inflammatory cytokines lower in CCR2-/- vs. wt mice. Pup brain and placental inflammation were similar. Using the IP LPS model, we found that all measures of arterial pressure increased in CCR2-/- but declined in wt mice. These data suggest that the CCL2/CCR2 system plays a critical role in the cardiovascular response to LPS and contributes to pup death but does not influence the onset of inflammation-induced PTL.
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- 2020
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3. Microvesicles as new therapeutic targets for the treatment of the acute respiratory distress syndrome (ARDS)
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Soni, Sanooj, Tirlapur, Nikhil, O’Dea, Kieran P., Takata, Masao, and Wilson, Michael R.
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ABSTRACTIntroduction: Acute respiratory distress syndrome (ARDS) is a heterogeneous and multifactorial disease; it is a common and devastating condition that has a high mortality. Treatment is limited to supportive measures hence novel pharmacological approaches are necessary. We propose a new direction in ARDS research; this means moving away from thinking about individual inflammatory mediators and instead investigating how packaged information is transmitted between cells. Microvesicles (MVs) represent a novel vehicle for inter-cellular communication with an emerging role in ARDS pathophysiology.Areas covered: This review examines current approaches to ARDS and emerging MV research. We describe advances in our understanding of microvesicles and focus on their pro-inflammatory roles in airway and endothelial signaling. We also offer reasons for why MVs are attractive therapeutic targets.Expert opinion: MVs have a key role in ARDS pathophysiology. Preclinical studies must move away from simple models toward more realistic scenarios while clinical studies must embrace patient heterogeneity. Microvesicles have the potential to aid identification of patients who may benefit from particular treatments and act as biomarkers of cellular status and disease progression. Understanding microvesicle cargoes and their cellular interactions will undoubtedly uncover new targets for ARDS.
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- 2019
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4. Asymptotic analysis of dipolar mixed modes of oscillations in red giant stars
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Takata, Masao
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Dipolar modes of solar-like oscillations of red giant stars are analyzed asymptotically. Because of the high mass concentration in the helium core, the oscillations of the stars are composed of internal gravity waves in the core and acoustic waves in the envelope. The two types of oscillations interact with each other through a thin intermediate evanescent region to form an eigenmode of the mixed character. The process of the eigenmode formation is analyzed by assuming that the wavelength of the oscillations is much shorter than the scale height of the equilibrium stellar structure. Special care is paid to the following two points: (1) the effect of the perturbation to the gravitational potential is fully taken into account; (2) the interaction between the gravity waves in the core and the acoustic waves in the envelope can be strong. The condition that every eigenfrequency of the oscillations should satisfy is formulated. Also discussed are the amplitude ratio between the core and the envelope, and the transmission and reflection of the progressive-wave solutions at the intermediate evanescent region. The analysis should be of fundamental use in the interpretation of the observed solar-like oscillations in red giant stars.
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- 2024
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5. Ventilation following established ARDS: a preclinical model framework to improve predictive power
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Oakley, Charlotte, Koh, Marissa, Baldi, Rhianna, Soni, Sanooj, O'Dea, Kieran, Takata, Masao, and Wilson, Michael
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BackgroundDespite advances in understanding the pathophysiology of acute respiratory distress syndrome, effective pharmacological interventions have proven elusive. We believe this is a consequence of existing preclinical models being designed primarily to explore biological pathways, rather than predict treatment effects. Here, we describe a mouse model in which both therapeutic intervention and ventilation were superimposed onto existing injury and explored the impact of β-agonist treatment, which is effective in simple models but not clinically.MethodsMice had lung injury induced by intranasal lipopolysaccharide (LPS), which peaked at 48 hours post-LPS based on clinically relevant parameters including hypoxaemia and impaired mechanics. At this peak of injury, mice were treated intratracheally with either terbutaline or tumour necrosis factor (TNF) receptor 1-targeting domain antibody, and ventilated with moderate tidal volume (20 mL/kg) to induce secondary ventilator-induced lung injury (VILI).ResultsVentilation of LPS-injured mice at 20 mL/kg exacerbated injury compared with low tidal volume (8 mL/kg). While terbutaline attenuated VILI within non-LPS-treated animals, it was ineffective to reduce VILI in pre-injured mice, mimicking its lack of clinical efficacy. In contrast, anti-TNF receptor 1 antibody attenuated secondary VILI within pre-injured lungs, indicating that the model was treatable.ConclusionsWe propose adoption of a practical framework like that described here to reduce the number of ultimately ineffective drugs reaching clinical trials. Novel targets should be evaluated alongside interventions which have been previously tested clinically, using models that recapitulate the (lack of) clinical efficacy. Within such a framework, outperforming a failed pharmacologic should be a prerequisite for drugs entering trials.
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- 2019
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6. Progesterone, the maternal immune system and the onset of parturition in the mouse†
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Edey, Lydia F, Georgiou, Hector, O’Dea, Kieran P, Mesiano, Sam, Herbert, Bronwen R, Lei, Kaiyu, Hua, Renyi, Markovic, Danijela, Waddington, Simon N, MacIntyre, David, Bennett, Philip, Takata, Masao, and Johnson, Mark R
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The role of progesterone (P4) in the regulation of the local (uterine) and systemic innate immune system, myometrial expression of connexin 43 (Cx-43) and cyclooxygenase 2 (COX-2), and the onset of parturition was examined in (i) naïve mice delivering at term; (ii) E16 mice treated with RU486 (P4-antagonist) to induce preterm parturition; and (iii) in mice treated with P4 to prevent term parturition. In naïve mice, myometrial neutrophil and monocyte numbers peaked at E18 and declined with the onset of parturition. In contrast, circulating monocytes did not change and although neutrophils were increased with pregnancy, they did not change across gestation. The myometrial mRNA and protein levels of most chemokines/cytokines, Cx-43, and COX-2 increased with, but not before, parturition. With RU486-induced parturition, myometrial and systemic neutrophil numbers increased before and myometrial monocyte numbers increased with parturition only. Myometrial chemokine/cytokine mRNA abundance increased with parturition, but protein levels peaked earlier at between 4.5 and 9 h post-RU486. Cx-43, but not COX-2, mRNA expression and protein levels increased prior to the onset of parturition. In mice treated with P4, the gestation-linked increase in myometrial monocyte, but not neutrophil, numbers was prevented, and expression of Cx-43 and COX-2 was reduced. On E20 of P4 supplementation, myometrial chemokine/cytokine and leukocyte numbers, but not Cx-43 and COX-2 expression, increased. These data show that during pregnancy P4 controls myometrial monocyte infiltration, cytokine and prolabor factor synthesis via mRNA-dependent and independent mechanisms and, with prolonged P4 supplementation, P4 action is repressed resulting in increased myometrial inflammation.Progesterone independently regulates the maternal immune system and the onset of parturition in the mouse.
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- 2018
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7. Intravascular donor monocytes play a central role in lung transplant ischaemia-reperfusion injury
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Tatham, Kate Colette, O'Dea, Kieran Patrick, Romano, Rosalba, Donaldson, Hannah Elizabeth, Wakabayashi, Kenji, Patel, Brijesh Vipin, Thakuria, Louit, Simon, Andre Rudiger, Sarathchandra, Padmini, Marczin, Nandor, and Takata, Masao
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RationalePrimary graft dysfunction in lung transplant recipients derives from the initial, largely leukocyte-dependent, ischaemia-reperfusion injury. Intravascular lung-marginated monocytes have been shown to play key roles in experimental acute lung injury, but their contribution to lung ischaemia-reperfusion injury post transplantation is unknown.ObjectiveTo define the role of donor intravascular monocytes in lung transplant-related acute lung injury and primary graft dysfunction.MethodsIsolated perfused C57BL/6 murine lungs were subjected to warm ischaemia (2 hours) and reperfusion (2 hours) under normoxic conditions. Monocyte retention, activation phenotype and the effects of their depletion by intravenous clodronate-liposome treatment on lung inflammation and injury were determined. In human donor lung transplant samples, the presence and activation phenotype of monocytic cells (low side scatter, 27E10+, CD14+, HLA-DR+, CCR2+) were evaluated by flow cytometry and compared with post-implantation lung function.ResultsIn mouse lungs following ischaemia-reperfusion, substantial numbers of lung-marginated monocytes remained within the pulmonary microvasculature, with reduced L-selectin and increased CD86 expression indicating their activation. Monocyte depletion resulted in reductions in lung wet:dry ratios, bronchoalveolar lavage fluid protein, and perfusate levels of RAGE, MIP-2 and KC, while monocyte repletion resulted in a partial restoration of the injury. In human lungs, correlations were observed between pre-implantation donor monocyte numbers/their CD86 and TREM-1 expression and post-implantation lung dysfunction at 48 and 72 hours.ConclusionsThese results indicate that lung-marginated intravascular monocytes are retained as a ‘passenger’ leukocyte population during lung transplantation, and play a key role in the development of transplant-associated ischaemia-reperfusion injury.
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- 2018
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8. The response of the innate immune and cardiovascular systems to LPS in pregnant and nonpregnant mice†
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Zöllner, Julia, Howe, Laura G., Edey, Lydia F., O’Dea, Kieran P., Takata, Masao, Gordon, Fabiana, Leiper, James, and Johnson, Mark R.
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Sepsis is the leading cause of direct maternal mortality, but there are no data directly comparing the response to sepsis in pregnant and nonpregnant (NP) individuals. This study uses a mouse model of sepsis to test the hypothesis that the cardiovascular response to sepsis is more marked during pregnancy. Female CD1 mice had radiotelemetry probes implanted and were time mated. NP and day 16 pregnant CD-1 mice received intraperitoneal lipopolysaccharide (LPS; 10 μg, serotype 0111: B4). In a separate study, tissue and serum (for RNA, protein and flow cytometry studies), aorta and uterine vessels (for wire myography) were collected after LPS or vehicle control administration. Administration of LPS resulted in a greater fall in blood pressure in pregnant mice compared to NP mice. This occurred with similar changes in the circulating levels of cytokines, vasoactive factors, and circulating leukocytes, but with a greater monocyte and lesser neutrophil margination in the lungs of pregnant mice. Baseline markers of cardiac dysfunction and apoptosis as well as cytokine expression were higher in pregnant mice, but the response to LPS was similar in both groups as was the ex vivo assessment of vascular function. In pregnant mice, nonfatal sepsis is associated with a more marked hypotensive response but not a greater immune response. We conclude that endotoxemia induces a more marked hypotensive response in pregnant compared to NP mice. These changes were not associated with a more marked systemic inflammatory response in pregnant mice, although monocyte lung margination was greater. The more marked hypotensive response to LPS may explain the greater vulnerability to some infections exhibited by pregnant women.In pregnant mice, nonfatal sepsis is associated with a more marked hypotensive response but not a greater immune response.
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- 2017
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9. The role of ex vivo lung perfusion in lung transplantation
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Tatham, Kate, O’Dea, Kieran, Wakabayashi, Kenji, Marczin, Nandor, and Takata, Masao
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Whilst lung transplantation is a viable solution for end-stage lung disease, donor shortages, donor lung inflammation and perioperative lung injury remain major limitations. Ex vivo lung perfusion has emerged as the next frontier in lung transplantation to address and overcome these limitations, with multicentre clinical trials ongoing in the UK, rest of Europe and North America. Our research seeks to identify the poorly understood cellular and molecular mechanisms of primary graft dysfunction through the development of an isolated perfused lung model of transplantation and investigation of the role of pulmonary inflammation in this paradigm.
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- 2015
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10. Exhaled breath acetone for therapeutic monitoring in pneumonia using selected ion flow tube mass spectrometry (SIFT-MS)
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Huang, Juzheng, Kumar, Sacheen, Singanayagam, Aran, George, Peter M., Kon, Onn Min, Takata, Masao, and Hanna, George B.
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Exhaled breath analysis of volatile organic compounds (VOCs) has great potential in terms of measuring physiological response to treatment. Exhaled breath acetone was measured in patients with community acquired pneumonia for the duration of their in-hospital treatment using Selected Ion Flow Tube-Mass Spectrometry (SIFT-MS). A positive correlation was observed between exhaled breath acetone concentrations and same-day serum C-reactive protein (CRP) levels. Exhaled breath acetone concentrations and CRP levels decreased in the range of 76–90% and 67–80%, respectively, from the day of admission to the day of discharge. This proof of concept study demonstrates the potential of SIFT-MS exhaled breath analysis as a non-invasive tool for clinical therapeutic monitoring.
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- 2013
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11. Dipolar Oscillations of Stars in General Relativity
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Takata, Masao
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We present a concise second-order system of ordinary differential equations that describes the adiabatic dipolar oscillation of spherically-symmetric stars in general relativity. The derivation of the system is accomplished by formulating the equations as a Hamiltonian system, and reconsidering a known algebraic relation among the perturbed variables as an integral of the system. The new formulation allows us to examine the structure of eigenfunctions and properties of the eigenfrequency spectrum, so that we can establish a scheme to classify eigenmodes into p-modes and g-modes with mathematical rigorousness. We can also discuss the condition for the existence of dynamically-unstable modes. All of these analyses are totally analogous to those developed in the Newtonian case.
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- 2008
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12. Analysis of Adiabatic Dipolar Oscillations of Stars
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Takata, Masao
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We theoretically discuss adiabatic dipolar oscillations of stars, fully taking into account the variation in the gravitational field. By suitably choosing the dependent variables, and using the first integral specific to dipolar oscillations, we derive the second-order system of ordinary differential equations, which is the same in form as that obtained by neglecting the Eulerian perturbation to the gravitational potential. The derived system suggests that the conventional expressions of the critical frequencies should be corrected. In addition, we present a rigorous scheme to classify the dipolar eigenmodes of linear adiabatic oscillations of spherically symmetric stars.
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- 2006
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13. First Integrals of Adiabatic Stellar Oscillations
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Takata, Masao
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We consider the equations of linear adiabatic oscillations of stars analytically. There are two known first integrals of nonradial oscillations of spherically symmetric stars, which exist for any stellar structure. One is obtained by integrating the linearized Poisson equation in the case of radial oscillations. The other is derived from momentum conservation in the case of dipolar oscillations. Both of these integrals reduce the order of the differential equations from four to two, which is not trivial. We find that this property can be understood from the fact that the problem of adiabatic stellar oscillations can be formulated as a Hamiltonian system. We then examine the symmetry of the system that corresponds to these first integrals. We finally show that there is no other first integral that is valid for arbitrary structures of stars.
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- 2006
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14. Momentum Conservation and Mode Classification of the Dipolar Oscillations of Stars
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Takata, Masao
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Despite their apparent simplicity, the dipole modes of stellar oscillations are theoretically less tractable than the other nonradial modes. This is because neglecting the Eulerian perturbation to the gravitational potential (the Cowling approximation), which greatly simplifies the governing equations, is not always very accurate in the case of dipole modes. In this paper, we first derive an integral that is specific to dipole-mode oscillations. It is then shown that the fourth-order differential equation, which governs the nonradial adiabatic oscillations of stars, is reduced to a (linear) second-order equation in the dipole case without assuming the Cowling approximation. Based on this second-order equation, we discuss how to classify the adiabatic dipole modes theoretically. We specifically propose a scheme that allocates a unique index to each of the dipole modes.
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- 2005
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15. Computation of the Adiabatic Eigenmodes of Stars Using the Riccati Method
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Takata, Masao and Löffler, Wolfgang
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In stellar oscillation problems, it is often necessary to compute a large number of stellar eigenmodes with wildly varying radial orders and angular degrees. Conventionally the relaxation method is used for this purpose. This method is, however, fraught with several numerical issues, which make it cumbersome and tedious to write the corresponding computer programs. For this reason we adopt the Riccati method as an alternative, in which the original system of linear equations is transformed into a nonlinear matrix Riccati equation. The dependent variable of the converted equation does not retain the dependent variables of the original linear equations themselves, but keeps the relations among them. This method is particularly useful when we compute eigenmodes, where the amplitudes of the eigenfunctions vary by many orders of magnitude, since the ratios of the amplitudes generally show much less variation than the amplitudes themselves. The Riccati method was successfully applied to the problems of nonadiabatic stellar oscillations in previous studies. Our aim is to do the same for the adiabatic case.
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- 2004
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16. Hydrogen Abundance in the Tachocline Layer of the Sun
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Takata, Masao and Shibahashi, Hiromoto
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Sound speed inversions of the Sun show that the profile of the relative difference between the Sun and the standard solar model has a sharp peak around $r / {{{R}_{\odot}}} = 0.65$, which is the location of the tachocline layer found by rotation inversions. It has been suggested that this sharp peak would be due to the difference, between the Sun and the model, in the hydrogen abundance in the tachocline layer, possibly caused by the weak-mixing process. In this paper, we quantitatively discuss the hydrogen abundance in the tachocline layer based on a seismic solar model, which was constructed using the sound speed and density profiles as well as the depth of the convection zone obtained by helioseismology. One of the important characteristics of the seismic solar model is that it gives us a hydrogen profile as a part of the solution. We find that the hydrogen abundance of the seismic solar model decreases more mildly than that of the standard solar models constructed by incorporating the diffusion process. This feature hardly depends on the profile of the heavy elements as well as the uncertainties in the opacity and the equation of state.
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- 2003
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17. Intratracheal anti-tumor necrosis factor-α antibody attenuates ventilator-induced lung injury in rabbits
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Imai, Yumiko, Kawano, Toshio, Iwamoto, Sanju, Nakagawa, Satoshi, Takata, Masao, and Miyasaka, Katsuyuki
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To evaluate the role of tumor necrosis factor (TNF)-α in the pathogenesis of ventilator-induced lung injury, we1) measured TNF-α production in the lung caused by conventional mechanical ventilation (CMV) and2) evaluated the protective effect of anti-TNF-α antibody (Ab) in saline-lavaged rabbit lungs. After they received saline lung lavage, rabbits were intratracheally instilled with 1 mg/kg of polyclonal anti-TNF-α Ab in the high-dose group (n= 6), 0.2 mg/kg of anti-TNF-α Ab in the low-dose group (n= 6), serum IgG fraction in the Ab control group (n= 6), and saline in the saline control group (n= 7). Animals then underwent CMV for 4 h. Levels of TNF-α in lung lavage fluid were significantly higher after CMV than before in both control groups. Pretreatment with intratracheal instillation of high and low doses of anti-TNF-α Ab improved oxygenation and respiratory compliance, reduced the infiltration of leukocytes, and ameliorated pathological findings. CMV led to TNF-α production in the lungs, and intratracheal instillation of anti-TNF-α Ab attenuated CMV-induced lung injury in this model.
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- 1999
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18. Influence of increased abdominal pressure on steady-state cardiac performance
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Kitano, Yoshihiro, Takata, Masao, Sasaki, Nobuyoshi, Zhang, Qinming, Yamamoto, Shin, and Miyasaka, Katsuyuki
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The effect of steady-state increases in abdominal pressure (Pab) on cardiac performance was studied in seven acutely instrumented swine with pneumoperitoneum (PP). The animal was placed on volume-preset ventilation, and PP was created by air insufflation. Cardiac output (CO), right atrial (Pra), left atrial (Pla), pericardial (Ppe), and abdominal inferior vena cava pressures (Pivc) were measured while Pab was increased from baseline to 7.5, 15, and 30 mmHg (PP7.5, PP15, and PP30, respectively). Cardiac function curves of the right and left ventricle (RV and LV, respectively) were compared between baseline and PP30. CO presented biphasic changes, with an inital slight increase at PP7.5 followed by a fall at PP30. A significant discrepancy was observed between Pra and Pivc at PP15 and PP30, consistent with development of a “vascular waterfall.” Transmural Pla (Pla − Ppe) showed parallel changes with CO, whereas transmural Pra (Pra − Ppe) exhibited a sustained increase. The RV cardiac-function curve was more depressed than was that of the LV at PP30; this suggests an increased RV afterload produced by the elevated airway pressure. These results support the hypothesis that our previously proposed concept of abdominal vascular zone conditions (M. Takata, R. A. Wise, and J. L. Robotham.J. Appl. Physiol.69: 1961–1972, 1990) is also applicable to steady-state hemodynamic analyses. The abdominal zones appear to play an important role in determining CO, with increases in Pab, by modulating systemic venous return and the LV preload. Simultaneous measurements of Pra and Pivc may provide useful information in the hemodynamic care of patients with elevated Pab.
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- 1999
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19. Coupled vs. uncoupled pericardial constraint: effects on cardiac chamber interactions
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Takata, Masao, Harasawa, Yasuhiko, Beloucif, Sadek, and Robotham, James L.
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Takata, Masao, Yasuhiko Harasawa, Sadek Beloucif, and James L. Robotham. Coupled vs. uncoupled pericardial constraint: effects on cardiac chamber interactions. J. Appl. Physiol.83(6): 1799–1813, 1997.—The effects of pericardial constraint on cardiac chamber interactions were evaluated by mathematical model analyses based on a novel concept of coupled vs. uncoupled pericardial constraint. We hypothesized that the nature of pericardial constraint can be classified as a “coupled” constraint exerted by uniform liquid pressure or an “uncoupled” constraint exerted by regional surface pressure. The numerical solution of the model of atrioventricular interaction produced the characteristic waveforms in venous flows and right atrial/ventricular pressures in classical pericardial diseases. Coupled constraint accounted for the patterns in cardiac tamponade; uncoupled constraint accounted for those in constrictive pericarditis. Analytic solution of the model of ventricular interdependence demonstrated that coupled constraint (tamponade) produced greater gains in ventricular interdependence, increasing the occurrence of pulsus paradoxus, whereas uncoupled constraint (constriction) produced a greater effective right ventricular elastance, increasing the likelihood of Kussmaul’s sign. Thus the concept of coupled vs. uncoupled constraint may offer a coherent framework to understand the characteristic steady-state and respiratory-induced hemodynamic events in multiple forms of pericardial diseases.
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- 1997
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20. A Seismic Solar Model Deduced from the Sound-Speed Distribution and an Estimate of the Neutrino Fluxes
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Shibahashi, Hiromoto and Takata, Masao
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We have deduced the density, pressure, temperature, and hydrogen profiles in the solar interior by solving the basic equations governing the stellar structure with the imposition that the sound-speed profile is that determined by the helioseismic data of Libbrecht et al. (1990; AAA 52.080.103) and Jiménez et al. (1988; AAA 45.080.041). This approach is completely different from that of the standard solar model, and is based on more experimentally well-determined data. We solved the equations by requiring that the mass and mean molecular weight at the surface match the solar mass and a certain fixed value, respectively, as the outer boundary conditions. Together with these conditions and the appropriate inner boundary conditions, these equations were reduced to a boundary-value problem. We examined whether the luminosity at the surface matches the observed value. The error levels were estimated by a Monte-Carlo simulation with Gaussian noise on the sound-speed profile. The thus-constructed seismic model marginally satisfies the luminosity condition, L(R⊙) = L⊙, at the 3σlevel. Using this seismic model, we estimated the neutrino fluxes, and found that the 8B neutrino flux is about 60% of that of the standard solar model. This model does not seem to contradict the Kamiokande neutrino detection experiment. The 7Be neutrino flux of the model is about 20% smaller than the standard solar model, and the pp-neutrino flux of the model is almost the same as that of the standard solar model. We estimated the total neutrino capture rate of the chlorine experiment (Homestake) and that of the gallium experiments (GALLEX and SAGE), except for a contribution from the CNO cycle, by scaling the capture rates based on the standard solar model. The thus-estimated capture rates are 5.62 SNU and 117 SNU, respectively, and are higher than those observed at the 3σerror level.
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- 1996
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21. Solar Models Based on Helioseismology and the Solar Neutrino Problem
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Takata, Masao and Shibahashi, Hiromoto
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We have determined the sound-speed profile in the Sun by carrying out an asymptotic inversion of the helioseismic data from the Low-Degree (l) Oscillation Experiment (LOWL), the Global Oscillation Network Group (GONG), VIRGO on SOHO, the High-l Helioseismometer (HLH), and observations made at the South Pole. We then deduce the density, pressure, temperature, and elemental composition profiles in the solar radiative interior by solving the basic equations governing the stellar structure, with the imposition of the determined sound-speed profile and with a constraint on the depth of the convection zone obtained from helioseismic analysis and the ratio of the metal abundance to the hydrogen abundance at the photosphere. With the exception of the treatment of elements relevant to nuclear reactions, we assume that Z is homogeneous. The chemical composition profiles of hydrogen and helium are then obtained as a part of the solutions. Using the resulting seismic model, we estimate the neutrino fluxes and the neutrino capture rates for the chlorine, gallium, and water Cerenkov experiments. Even if we take into account uncertainties in various input physics, the estimated capture rates are still significantly larger than the observation.
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- 1998
22. Flow velocity profile of the pulmonary artery measured by the continuous cardiac output monitoring catheter
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Miyasaka, Keiko, Takata, Masao, and Miyasaka, Katsuyuki
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The KATS catheter (continuous arterial thermodeprivation system catheter) measures the blood flow velocity of the pulmonary artery (PA) by thermodeprivation which enables continuous determination of cardiac output. The accuracy of this system may depend on the degree of uniformity of flow velocity in the PA, because small movements of the catheter within the PA are inevitable with a beating heart. We evaluated the flow velocity profile of the PA in seven anaesthetized open-chest dogs to assess these potential errors. A custom-made stiff catheter, at the tip of which was incorporated the flow velocity sensor of the KATS catheter, was used to penetrate the main PA in the short axis direction (perpendicular to flow direction) or the long axis direction (along flow direction). The stiff catheter was moved in increments of 2.5 mm, and flow velocity was recorded. The wall-to-wall distance of the PA along each direction was divided into five sections (S1to S5for the short axis, and L1to L5for the long axis). Flow velocity data for each section were averaged and presented as relative values against the control mid-point velocity. Along the short axis, flow velocity was 0.41 ± 0.20 (SD), 1.00 ± 0.10, 1.03 ± 0.10, 1.08 ± 0.13 and 0.49 ± 0.26 from S1to S5, i.e., lower in S1and S5which were close to the vascular walls (P < 0.05) but uniform in other areas. Along the long axis, flow velocity was 0.28 ± 0.28, 0.88 ± 0.09, 0.94 ± 0.08, 1.06 ± 0.25 and 1.28 ± 0.50 from L1to L5. Thus, flow velocity was lower in L1which was close to the bifurcation (P < 0.05), slightly higher in L5close to the pulmonary valve, but uniform in other areas. These results suggest that the profile of blood flow velocity is relatively uniform within the main PA except in areas close to the vessel walls or valve. We conclude that movement of the catheter within the vessel would not substantially influence the accuracy of the KATS catheter system as long as the flow velocity sensor of the catheter stays within the main PA.
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- 1993
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23. The Local and Systemic Immune Response to Intrauterine LPS in the Prepartum Mouse1
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Edey, Lydia F., O'Dea, Kieran P., Herbert, Bronwen R., Hua, Renyi, Waddington, Simon N., MacIntyre, David A., Bennett, Philip R., Takata, Masao, and Johnson, Mark R.
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Inflammation plays a key role in human term and preterm labor (PTL). Intrauterine LPS has been widely used to model inflammation-induced complications of pregnancy, including PTL. It has been shown to induce an intense myometrial inflammatory cell infiltration, but the role of LPS-induced inflammatory cell activation in labor onset and fetal demise is unclear. We investigated this using a mouse model of PTL, where an intrauterine injection of 10 μg of LPS (serotype 0111:B4) was given at E16 of CD1 mouse pregnancy. This dose induced PTL at an average of 12.7 h postinjection in association with 85% fetal demise. Flow cytometry showed that LPS induced a dramatic systemic inflammatory response provoking a rapid and marked leucocyte infiltration into the maternal lung and liver in association with increased cytokine levels. Although there was acute placental inflammatory gene expression, there was no corresponding increase in fetal brain inflammatory gene expression until after fetal demise. There was marked myometrial activation of NFκB and MAPK/AP-1 systems in association with increased chemokine and cytokine levels, both of which peaked with the onset of parturition. Myometrial macrophage and neutrophil numbers were greater in the LPS-injected mice with labor onset only; prior to labor, myometrial neutrophils and monocytes numbers were greater in PBS-injected mice, but this was not associated with an earlier onset of labor. These data suggest that intrauterine LPS induces parturition directly, independent of myometrial inflammatory cell infiltration, and that fetal demise occurs without fetal inflammation. Intrauterine LPS provokes a marked local and systemic inflammatory response but with limited inflammatory cell infiltration into the myometrium or placenta.
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- 2016
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24. Loss of epithelial Gqand G11signaling inhibits TGFβ production but promotes IL-33–mediated macrophage polarization and emphysema
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John, Alison E., Wilson, Michael R., Habgood, Anthony, Porte, Joanne, Tatler, Amanda L., Stavrou, Anastasios, Miele, Gino, Jolly, Lisa, Knox, Alan J., Takata, Masao, Offermanns, Stefan, and Jenkins, R. Gisli
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Signaling by Gq/11is required for optimal TGFβ activation in the lung to prevent inflammation.
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- 2016
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25. Physical formulation of mixed modes of stellar oscillations
- Author
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Takata, Masao
- Abstract
The frequency condition for eigenmodes of nonradial stellar oscillations with a mixed character, which have been extensively detected in red giants and subgiants, is generally examined by a simple physical model based on a progressive-wave picture. The coupling coefficient between the gravity-wave oscillation in the core and the acoustic-wave oscillation in the envelope is expressed in terms of the reflection coefficient at the intermediate evanescent region. This relation is fully consistent with the recent asymptotic analysis for dipolar modes, but disagrees with the conventional asymptotic analysis, which assumes that the coupling is weak. The expression for the amplitude ratio between the core and envelope oscillations is also derived. The upper and lower bounds of the ratio are found to be determined by the reflection coefficient at the intermediate region. It is also argued that the eigenmode condition should appropriately be modified if the wave generated near the surface and transmitted to the core is (partially) lost either by damping or scattering in the core. The developed formulation opens a possibility to characterize the core damping (or scattering) of the red giant stars in terms of the formal reflection coefficient at the inner boundary of the inner cavity, which would provide a valuable insight into those physical processes.
- Published
- 2016
- Full Text
- View/download PDF
26. Selective Liquid-Membrane Transport of Nitro-phenols by a Simple and Costless Carrier. An Application of the Results of Centrifugal Partition Chromatography
- Author
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Araki, Takeo, Kubo, Yasuo, Takata, Masao, Gohbara, Shinji, and Yamamoto, Toshiyuki
- Abstract
By applying the separation data of countercurrent type chromatography (centrifugal partition chromatography(CPC)) to liquid-membrane transport system(LMT), an effective simple carrier for selective LMT was found. This observation will be an important suggestion for finding out a costless carrier of selective LMT for weakly ionic or non-ionic substrates.
- Published
- 1987
- Full Text
- View/download PDF
27. Rosette Modes of Oscillations of Rotating Stars Caused by Close Degeneracies. I. Axisymmetric Modes
- Author
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Takata, Masao and Saio, Hideyuki
- Abstract
We present an analysis of unique axisymmetric eigenmodes of oscillations in rigidly rotating stars, which have been recently discovered numerically in the frequency region of low-order gravity modes of the polytropic model with index 3, and named as rosette modes after their structure of the eigenfunctions. We show that the appearance of rosette modes in the presence of slow rotation is caused by a close degeneracy in the frequency among several eigenmodes in the non-rotating case. Regarding the effect of the Coriolis force on stellar oscillations as a small perturbation, and applying quasi-degenerate perturbation theory, we can successfully reproduce the structure of rosette modes as a linear combination of several unperturbed eigenmodes, which have almost the same frequency and successive spherical degrees of the same parity. We confirm that the eigenfrequencies and the structure of the eigenfunctions that are determined by the perturbative technique are consistent with the results of more direct numerical computations, which are based on the decomposition of the eigenfunctions into a series of spherical harmonics. We discuss the characteristics of rosette modes in detail.
- Published
- 2013
- Full Text
- View/download PDF
28. Mode Classification of Linear Adiabatic Oscillations of Spherically Symmetric Stars
- Author
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Takata, Masao
- Abstract
We propose a mathematical scheme to classify the eigenmodes of linear adiabatic oscillations of spherically symmetric stars, while fully taking account of the perturbation to the gravitational potential. The scheme allows us to allocate a unique and continuous integral index (the radial order) to each non-degenerate eigenmode with a positive squared eigenfrequency of any stellar structure, whereas a pair of degenerate eigenmodes, if exist, are assigned a unique pair of indices. The indices of the eigenmodes are invariant against any continuous change in the equilibrium structure. Based on these indices, we can unambiguously define the three kinds of eigenmodes of adiabatic stellar oscillations: p-modes, g-modes, and f-modes.
- Published
- 2012
- Full Text
- View/download PDF
29. Continuous real-time measurement of tumor necrosis factor-α converting enzyme activity on live cells.
- Author
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Alvarez-Iglesias, Montserrat, Wayne, Gareth, O'Dea, Kieran P., Amour, Augustin, and Takata, Masao
- Published
- 2009
- Full Text
- View/download PDF
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