120 research outputs found
Unequal effects of renin-angiotensin system inhibitors in acute cardiac dysfunction induced by isoproterenol
Ohta, T; Hasebe, N; Tsuji, S; Izawa, K; Jin, YT; Kido, S; Natori, S; Sato, M; Kikuchi, K, AMERICAN JOURNAL OF PHYSIOLOGY-HEART AND CIRCULATORY PHYSIOLOGY, 287(6), H2914-H2921, 2004. "Copyright 2004 by the American Physical Society."
publisherSeveral clinical trials have demonstrated that angiotensin-converting enzyme inhibitor (ACEI) and angiotensin II type 1 receptor blocker (ARB) are equally effective in the treatment of chronic heart failure. However, this has not been confirmed for acute cardiac dysfunction. We examined whether ACEI or ARB prevents isoproterenol-induced acute left ventricular (LV) dysfunction in dogs. LV dysfunction induced by a large dose of isoproterenol (1 µg·kg^–1·min^–1, 3-h infusion) was compared in dogs treated with ACEI (temocaprilat) or ARB (olmesartan). Atrial pacing induced a constant heart rate and use of adjustable aortic banding provided a nearly constant afterload. LV systolic function (LV dP/dt, fractional shortening, and ejection fraction) and diastolic function (γ and LV end-diastolic pressure) were significantly deteriorated after isoproterenol infusion. The LV dysfunction was almost totally prevented by ARB but was only partially prevented by ACEI. The partial effect of ACEI was complemented by cotreatment with HOE-140, a bradykinin B_2 receptor antagonist. At baseline, the response to low doses of isoproterenol was significantly attenuated by ACEI but not by ARB, and the ACEI-induced attenuation was totally abolished by cotreatment with HOE-140. The response to isoproterenol was significantly attenuated after 3 h of excess isoproterenol loading, and it was almost completely preserved by ARB but not by ACEI. In conclusion, acute LV dysfunction and β-adrenergic desensitization induced by excess isoproterenol administration were almost totally prevented by ARB but only partially prevented by ACEI. These differences were attributable at least in part to bradykinin pathways activated by ACEI administration in acute LV dysfunction
Quantitative Evaluation of Pain during Electrocutaneous Stimulation using a Log-Linearized Peripheral Arterial Viscoelastic Model
In clinical practice, subjective pain evaluations, e.g., the visual analogue scale and the numeric rating scale, are generally employed, but these are limited in terms of their ability to detect inaccurate reports, and are unsuitable for use in anesthetized patients or those with dementia. We focused on the peripheral sympathetic nerve activity that responds to pain, and propose a method for evaluating pain sensation, including intensity, sharpness, and dullness, using the arterial stiffness index. In the experiment, electrocardiogram, blood pressure, and photoplethysmograms were obtained, and an arterial viscoelastic model was applied to estimate arterial stiffness. The relationships among the stiffness index, self-reported pain sensation, and electrocutaneous stimuli were examined and modelled. The relationship between the stiffness index and pain sensation could be modelled using a sigmoid function with high determination coefficients, where R2 ≥ 0.88, p < 0.01 for intensity, R2 ≥ 0.89, p < 0.01 for sharpness, and R2 ≥ 0.84, p < 0.01 for dullness when the stimuli could appropriately evoke dull pain.This work was supported by the Center of Innovation Program from Japan Science and Technology Agency.Supplementary information accompanies this paper at https://doi.org/10.1038/s41598-018-21223-1
Changes of Branched Chain Amino Acids and Tyrosine Ratio (BTR) after Hepatectomy
To clarify the clinical usefulness of measuring branched chain amino acids and tyrosine ratio (BTR), which is correlated with Fischer\u27s ratio, we examined the serum BTR level in 33 patients with liver diseases. Serum levels of branched-chain amino acids (BCAAs) and tyrosine were measured by the new enzymatic method, which costs inexpensive and is immediate compared to measuring Fischer\u27s ratio. BTR was calculated as ratio of concentration of BCAA to tyrosine. BTR was correlated with levels of albumin, transaminase and cholinesterase and was lower in patients with chronic viral hepatitis, Child B cirrhosis and portal hypertension. In 19 patients who underwent hepatic resection included 8 for major hepatectomy, resected volume, blood loss, operation time and background of liver diseases were not associated with changes of BTR after hepatectomy. In patients with prolonged jaundice, postoperative BTR level was significantly lower between day I and 7 after hepatectomy. We concluded that serum BTR level was correlated with poor liver function and monitoring of BTR levels after hepatectomy may be useful to evaluate degree of hepatic damage after liver surgery
Endozoochorous seed dispersal by sympatric mustelids, Martes melampus and Mustela itatsi, in western Tokyo, central Japan
We investigated seed dispersal by two sympatric mustelid species, the Japanese marten (Martes melampus) and Japanese weasel (Mustela itatsi), along an intercity forest path in western Tokyo, central Japan, from Jul 2007 to Jul 2008. We aimed to investigate the effect of food/habitat preference of these mustelids (martens are semi-arboreal frugivores while weasels are terrestrial carnivores) on their seed dispersal characteristics, which determine their efficacy as seed dispersers. In total, we analyzed 478 fecal samples collected from the two mustelids (Nmarten = 381, Nweasel = 97). The proportions of feces containing seeds for martens and weasels were 81.4% and 55.7%, respectively. The number of plant species whose seeds were found within the feces were 28 and 17, respectively. Almost all seeds within feces of both mustelids were intact. The number of plant species whose seeds were found within a single fecal sample ranged from one to four, but no significant difference was detected between the two mustelids. However, marten feces contained a significantly greater number of seeds of most plant species as well as total number of seeds than did weasel feces. The numbers of plant species and seeds represented in marten feces varied seasonally, but those represented in weasel feces did not. Our findings suggest the possibility that both mustelids act in some ways as seed dispersers, although martens seem to disperse a greater diversity and total amount of seeds
Simultaneous Transport of Chloride and Calcium Ions in Hydrated Cement Systems
This paper presents a new method for numerically calculating the concentration profiles of both solid calcium and total chloride ions (Cl−) in concrete in contact with 3% (0.5 mol/l) sodium chloride (NaCl) solution. Since the diffusion of ions present in the pore solution is a primary controlling factor, the application of mutual diffusion coefficients of corresponding ions that are influenced by the concentration of other coexisting ions is proposed. The method of calculation is based on the generalized form of Fick's First Law suggested by Onsager, which is composed of the Onsager phenomenological coefficient and the thermodynamic force between ions, which occurs according to the gradient of electrochemical potential in a multicomponent concentrated solution for the pore solution. In addition, the chemical equilibrium for Ca(OH)2 dissolution and C-S-H decalcification are also modeled and coupled with diffusion. Increased porosity due to dissolved Ca2+ and a chloride binding isotherm are taken into consideration. The concentration profiles of solid calcium and the presence of Friedel's salt in mortar specimens are experimentally identified by the X-ray diffraction method (XRD) and the thermal analysis (TG/DTA) as well as the total chloride profile using an acid extraction method after three years of exposure to 0.5 mol/l NaCl solution. This experimental result verifies the calculation result
Calculation of Diffusion Coefficient of Ion in Multicomponent Solution for Ion Movement
ABSTRACT: A method for calculating the mutual diffusion coefficients of an ion influenced by all other coexisting ions in the multicomponent solution for ion movement in concrete is presented in this paper. The method of calculation is based on the generalized form of Fick's first law suggested by Onsager, which is composed of the Onsager phenomenological coefficient and the thermodynamic force between ions that exerted by the gradient of electrochemical potential in the solution. As a result of verification by comparison with the experimental results by Saito H. et al., it is shown that by using the presented method of calculation, the calculated leaching amount of some ions exhibited close to the experimental results
- …