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12. Extended expression of liver functions of hepatocytes in collagen-contained cell aggregates (cell packs)

Author

Makoto Nakajima, Iizuka Masahiko, Yohei Hirai, Makoto Takashina, and Kyoko Takebe

Subjects
Immunoblotting, Clinical Biochemistry, Cell, Biomedical Engineering, Bioengineering, Biology, Mice, Albumins, medicine, Protein biosynthesis, Animals, RNA, Messenger, Cells, Cultured, Serum Albumin, Cell Aggregation, Mice, Inbred BALB C, Albumin, Rats, Inbred Strains, Cell Biology, Blotting, Northern, Culture Media, Rats, Cell biology, Transplantation, medicine.anatomical_structure, Liver, Biochemistry, Cell culture, Hepatocyte, Electrophoresis, Polyacrylamide Gel, Collagen, Liver function, Intracellular, Biotechnology
Abstract

The functions of hepatocytes under the collagen-contained cell aggregate (cell pack) conditions were studied using liver-specific protein synthesis. Freshly isolated murine hepatocytes were suspended in the medium containing collagen and centrifuged, and the resultant cell masses were cultured on the porous membranes floating on the medium. In these cultures cells were attached to each other three-dimensionally with collagen present in the intercellular spaces. Cultured hepatocytes in the cell pack maintained high and stable activity in the expression of their functions for more than 2 weeks, even when cultured with the medium lacking any hormones and serum, whereas hepatocytes in monolayer cultures lost their functions within a week. Similarly, when the cell packs of rat hepatocytes were transplanted into rat spleens, they could retain viability in the form of cell aggregate with the expression of liver-specific albumin mRNA at a higher level than in the transplanted cell suspensions. The lifespan and the initial expression level of hepatocellular functions in culture were similar to that of the cell pack in cell aggregates without collagen and in cellular monolayers on the collagen gel respectively. It was concluded that the condition where cells are in contact with each other has an important role in the expression of hepatocellular functions and collagen present in the intercellular spaces enhances the functional levels.

Published
1991

15. Development of a New Device for Diagnosis of Hypoxemia and Arrhythmia by SaO2 ECG Holter Monitoring

Author

Nakamoto, Takaaki, primary, Momoki, Shigeru, additional, Harasawa, Hiroshi, additional, Ohnuma, Noboru, additional, Kato, Shiro, additional, Hase, Tatsuya, additional, Kuga, Hideyo, additional, Kishiro, Izumi, additional, Ohno, Kunihiko, additional, Suzuki, Hidehiko, additional, Tokoyama, Kouki, additional, Okamoto, Shingo, additional, Takasaki, Keiji, additional, Saitoh, Koh‐ichi, additional, Tamamura, Kazuki, additional, Abe, Tetsuro, additional, and Iizuka, Masahiko, additional

Published
1997
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19. Angiographic and Coronary Risk Factor Analyses of Japanese Patients With Ischemic Heart Disease Before Age 40

Author

Ogawa, Kenichi, primary, Numao, Toshiyuki, additional, Iizuka, Masahiko, additional, Yanagisawa, Atsuo, additional, Yoshino, Hideaki, additional, Ishikawa, Kyozo, additional, Miyake, Fumihiko, additional, Matsumoto, Naoki, additional, Murayama, Masahiro, additional, Hasegawa, Nobuhiro, additional, Kobayashi, Akiyoshi, additional, Kikawada, Ryuichi, additional, Kinoshita, Shinichiro, additional, Muramatsu, Toshihiro, additional, Matsuo, Hiroshi, additional, Isshiki, Takaaki, additional, Ochiai, Masahiko, additional, and Miyashita, Hideo, additional

Published
1996
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34. The Extrarenal Effects of Atrial Natriuretic Peptide on Body Fluid Distribution

Author

Hirata, Yasunobu, primary, Ishii, Masao, additional, Fukui, Kazushige, additional, Sugimoto, Tokuichiro, additional, Atarashi, Keiichiro, additional, Matsuoka, Hiroaki, additional, Iizuka, Masahiko, additional, Sugimoto, Tsuneaki, additional, Sakamoto, Katsuyuki, additional, Kanai, Hiroshi, additional, Kangawa, Kenji, additional, and Matsuo, Hisayuki, additional

Published
1990
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37. Doppler echocardiographic-determined changes in left ventricular diastolic filling flow velocity during the lower body positive and negative pressure method

Author

Takahashi, Toshiyuki, primary, Iizuka, Masahiko, additional, Sato, Hiroshi, additional, Serizawa, Takashi, additional, Momomura, Shin-ichi, additional, Mochizuki, Takatoshi, additional, Kohmoto, Osami, additional, Aoyagi, Teruhiko, additional, Matsui, Hiroshi, additional, Ikenouchi, Hiroshi, additional, Sakamoto, Tsuguya, additional, and Sugimoto, Tsuneaki, additional

Published
1990
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39. Development of a New Device for Diagnosis of Hypoxemia and Arrhythmia by SaO2 ECG Holter Monitoring.

Author

Nakamoto, Takaaki, Momoki, Shigeru, Harasawa, Hiroshi, Ohnuma, Noboru, Kato, Shiro, Hase, Tatsuya, Kuga, Hideyo, Kishiro, Izumi, Ohno, Kunihiko, Suzuki, Hidehiko, Tokoyama, Kouki, Okamoto, Shingo, Takasaki, Keiji, Saitoh, Koh-ichi, Tamamura, Kazuki, Abe, Tetsuro, and Iizuka, Masahiko

Abstract

Background: We have developed a system to monitor, simultaneously and continuously, ambulatory SaO2 measured using a pulse-oximeter and ECG data for 24 hours. Methods: The ambulatory SaO2-ECG monitoring system consisted of a portable monitoring device (SM50) with two channels for ECG data and one channel for SaO2 data input; a sensor for SaO2 recording; and a pulse-oximeter. An ambulatory monitoring analyzer was used. The SaO2 report from the present analyzer included two types of data (i.e., a profile of heart rate [HR], pulse rate [PR], and SaO2 value per min), and a trend graph of HR, arrhythmia, ST level and slope, PR, and SaO2 per minute. We also designed and produced an analytical program to automatically remove noise errors relating to the SaO2 measurement. Results: Using this system, we performed a clinical study on ten healthy volunteers (Group N) and seven patients with chronic pulmonary diseases (Group CPD) to evaluate the usefulness of the system as a diagnostic means for respiratory failure and arrhythmia. Group N showed a stable value of 90% or over in SaO2 during the 24-hour monitoring while Group CPD showed values under 90% SaO2 in all patients at rest during the night or after a 15-minute walk. Transient atrial tachycardia (TAT) was observed in 3 of 7 CPD patients, and each episode was preceded by a decrease of SaO2. The occurrence of a single or double ventricular extrasystole was high in Group CPD compared with Group N (1.21 ± 0.89 vs 0.6%± 0.3%, P < 0.05), its occurrence was not associated with a decrease in SaO2. Conclusions: In outpatients, especially patients who are taken care of at home, the present system will certainly contribute greatly to the diagnosis of respiratory failure and arrhythmia as well as to evaluate the effects on these diseases of therapy. In addition it is suggested that in CPD, patients'hypoxemia may induce TAT. [ABSTRACT FROM AUTHOR]

Published
1997
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40. Analysis of cardiac assistance by latissimus dorsi cardiomyoplasty with a time varying elastance model.

Author

Sugiura, Seiryo, Harada, Kazumasa, Yokoyama, Ikuo, Momomura, Shin-ichi, Naruse, Yosihiro, Maku-uchi, Haruo, Serizawa, Takashi, Matsunaga, Hitoshi, Iizuka, Masahiko, Furuse, Akira, and Sugimoto, Tsuneaki

Abstract

Objective: The clinical use of skeletal muscle cardiomyoplasty is limited because of its inadequate haemodynamic benefits. To facilitate experimental and clinical efforts to improve the efficacy of this technique, a mathematical model was proposed and its validity was tested in acute experiments. Methods: The model was based on the assumption that the skeletal muscle wrapped around the heart behaves as a time varying elastance that is connected in series with another time varying elastance representing the native heart. From this model two predictions were made: (1) Skeletal muscle augments the contractility of the heart by increasing the slope (Ees) of the end systolic pressure-volume relation; (2) time varying elastance of the skeletal muscle chamber (Es(t)) can be estimated from that of the assisted heart. These predictions were examined in experiments. In nine anaesthetised, open chest dogs, preconditioned latissimus dorsi muscle was transposed to wrap the heart. Left ventricular pressure (catheter tipped micromanometer), and volume (conductance catheter) were measured while reducing the preload by vena caval occlusion to evaluate Ees with 1:2 (stimu1ation:heart beat ratio) stimulation of the skeletal muscle. Results: With the stimulation of latissimus muscle, the end systolic pressure-volume relation was linear and Ees increased from 8.6(SEM 2.4) to 11.9(SEM 3.4) mm Hg·ml−1. Estimated Es(t) reflected the stimulation pattern and could account for the mechanism of the cardiac assistance. Conclusions: Skeletal muscle cardiomyoplasty improved the haemodynamic variable (Ees) as predicted by a mathematical model.Cardiovascular Research 1993;27:997-1003 [ABSTRACT FROM PUBLISHER]

Published
1993

41. Estimation of left ventricular elastance without altering preload or afterload in the conscious dog.

Author

Nakamoto, Takaaki, Cheng, Che-Ping, Santamore, William P, and Iizuka, Masahiko

Abstract

Objective: The aim was to determine the slope (EES) of the left ventricular end systolic pressure-volume line (ESPVL) without altering preload or afterload in conscious dogs. Methods: Dogs (n=10) were instrumented to determine left ventricular volume from ultrasonic left ventricular internal dimensions, and to measure left ventricular pressure using a micromanometer. Studies were performed one to two weeks after instrumentation while the animals were conscious. ESPVL was determined from variably loaded left ventricular pressure-volume (P-V) loops generated by the vena caval occlusion. Contractile state was increased by intravenous dobutamine (8 μg·kg−1·min−1) and decreased by intravenous verapamil (10 mg) given after autonomic blockade. From a single normally ejecting beat, we calculated EES-single beat (mm Hg·ml−1) as peak isovolumetric pressure (Pmax) minus end systolic pressure divided by stroke volume. Sunagawa's technique was used to estimate Pmax by fitting the pressure during the isovolumetric contraction and relaxation as: P(t)=l/2 × Piso[1-cos(ωt+c)]+LVEDP, where Piso=peak isovolumetric developed pressure, LVEDP=left ventricular end diastolic pressure, c=constant accounting for variations in phase angle, and ω=2 π/T in which T is duration of contraction. Results: After dobutamine, EES increased, from 8.9(SEM 0.8) to 12.5(1.0) mm Hg·ml−1 (p < 0.05), and Epg-single beat increased from 9.1(0.9) to 12.0(1.4) mm Hg·ml−1 (p < 0.05). Conversely, after verapamil, EES decreased, from 11.1(1.2) to 6.3(1.1) mm Hg·ml−1, (p < 0.05), and EES-single beat also decreased, from 9.6(1.0) to 7.3(1.2) mm Hg·ml−1, (p < 0.05). Conclusions: EES calculated from one beat is similar to EES determined from variably loaded left ventricular loops and responds appropriately to inotropic stimulation. This technique provides a reasonable method to calculate EES from left ventricular pressure and stroke volume without altering preload or afterload.Cardiovascular Research 1993;27:868-873 [ABSTRACT FROM PUBLISHER]

Published
1993

42. Effects of new intravascular contrast agents on [Ca2+]i transients and contraction in cultured ventricular myocytes

Author

Kohmoto, Osami, Matsui, Hiroshi, Momomura, Shin-ichi, Serizawa, Takashi, Sugimoto, Tsuneaki, and Iizuka, Masahiko

Abstract

Summary We examined the effects of four kinds of intravascular contrast agents (amidtrizoic acid, iohexol, iopamidol, and ioxaglic acid) on [Ca2+]i transients (indo-1 fluorescence) and cell contraction (video motion analyzer), using cultured chick embryo ventricular myocytes. Exposure of ventricular myocytes to amidtrizoic acid (a conventional contrast agent) reduced the [Ca2+]i transients and the sensitivity of the contractile elements to [Ca2+]i. Ioxaglic acid (a low osmotic contrast agent) also reduced the [Ca2+]i transients, but did not significantly change the sensitivity of the contractile elements to [Ca2+]i. Neither iohexol nor iopamidol (nonionic contrast agents) reduced the [Ca2+]i transients, but both significantly decreased the sensitivity of the contractile elements to [Ca2+]i. A marked negative inotropic effect of amidtrizoic acid was caused by both calcium binding and hypertonicity. The less marked depression of contractility produced by ioxaglic acid is possibly the result of calcium binding, but is not caused by hypertonicity. The negative inotropism produced by nonionic contrast agents (iohexol and iopamidol) was due to hypertonicity, but not due to alterations in the [Ca2+]i transients.

Published
1992
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43. Translation of Human Interleukin 2 mRNA in Xenopus laevisOocytes

Author

Hirano, Toshio, Sudo, Tetsuo, Teranishi, Tsuyoshi, Fujimoto, Kouji, Iizuka, Masahiko, Kobayashi, Sigeyasu, and Onoue, Kaoru

Abstract

Poly(A)‐positive mRNA extracted from tonsillar mononuclear cells stimulated with phytohemagglutinin‐M and 12‐o‐tetradecanoyl phorbol 13‐acetate was successfully translated into biologically active interleukin 2 (IL‐2) in Xenopus laevisoocytes, and secreted into the incubation medium. In control experiments, the extract of oocytes injected with either poly(A)‐negative RNA or buffer did not show any IL‐2 activity. By sucrose density gradient centrifugation analysis, IL‐2 mRNA was found as a single peak corresponding to a sedimentation coefficient of 10‐11S.

Published
1983
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44. Structural Characterization of Recombinant Human Interferon‐Gammas Derived from Two Different Mammalian Cells

Author

Sano, Emiko, Kamata, Koichi, Okano, Kiyoshi, Yamazaki, Syojiro, Iizuka, Masahiko, and Kobayashi, Sigeyasu

Abstract

Recombinant human interferon‐gammas (rHuIFN‐γs) were obtained from two different mammalian cells (mouse C127 cells and Chinese hamster ovary, CHO, cells) cultured in a microcarrier culture system. Both rHuIFN‐γs were purified using sequential chromatographies for their comparison of structural properties. The peptide maps of HuIFN‐γs digested with V8 protease and Western blot analysis demonstrated that C127 cells yielded mainly about 25kDa component and CHO cells produced about 25kDa and about 20kDa components. By the identification of glycosylated peptides, it was suggested that 20kDa and 25kDa components are glycosylated at one and at two sites, respectively. C‐terminal amino acid sequence analysis indicated that both rHuIFN‐γs consisted of at least six different species lacking 2 to 16 amino acid residues from C‐terminus, so that C‐termini of both rHuIFN‐γs were slightly different from each other.

Published
1988
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45. Development of a New Device for Diagnosis of Hypoxemia and Arrhythmia by SaO2ECG Holter Monitoring

Author

Nakamoto, Takaaki, Momoki, Shigeru, Harasawa, Hiroshi, Ohnuma, Noboru, Kato, Shiro, Hase, Tatsuya, Kuga, Hideyo, Kishiro, Izumi, Ohno, Kunihiko, Suzuki, Hidehiko, Tokoyama, Kouki, Okamoto, Shingo, Takasaki, Keiji, Saitoh, Koh‐ichi, Tamamura, Kazuki, Abe, Tetsuro, and Iizuka, Masahiko

Abstract

Background: We have developed a system to monitor, simultaneously and continuously, ambulatory SaO2measured using a pulse‐oximeter and ECG data for 24 hours.

Published
1997
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46. Plasma concentrations of α-human atrial natriuretic polypeptide and cyclic GMP in patients with heart disease

Author

Hirata, Yasunobu, Ishii, Masao, Matsuoka, Hiroaki, Sugimoto, Tokuichiro, Iizuka, Masahiko, Uchida, Yasumi, Serizawa, Takeshi, Sato, Hiroshi, Kohmoto, Osami, Mochizuki, Takatoshi, Sugimoto, Tsuneaki, Miyata, Atsuro, Kangawa, Kenji, and Matsuo, Hisayuki

Abstract

Plasma concentrations of immunoréactive α-human atrial natriuretic polypeptide (iα-hANP) and cyclic guanosine monophosphate (cGMP) were measured in 70 patients with heart disease. Plasma concentrations of iα-hANP were directly related to the severity of heart disease (F = 29.61, p< 0.001). Plasma concentrations of iα-hANP were well correlated with pulmonary capillary wedge pressure (PCWP; r= 0.64, p< 0.001), mean pulmonary arterial pressure (PAP; r= 0.62, p< 0.001), and mean right atrial pressure (RAP; r= 0.75, p< 0.001). Plasma concentrations of cGMP were also directly related to the severity of heart disease (F = 13.61, p< 0.001) and highly correlated with plasma concentrations of iα-hANP (r= 0.73, p< 0.001). Plasma concentrations of cGMP were also closely correlated with PCWP (r= 0.69, p< 0.001), mean PAP (r= 0.61, p< 0.001), and mean RAP (r= 0.60, p< 0.001). The iα-hANP concentrations of plasma samples obtained from the coronary sinus were approximately fourfold higher than those of samples obtained from the pulmonary artery, whereas cGMP concentrations were comparable in plasma samples obtained from either site. Elevation of cGMP concentrations following intravenous infusion of synthetic α-hANP was comparable in plasma samples obtained from the coronary sinus and the pulmonary artery. These findings suggest that elevated plasma concentrations of iα-hANP in cardiac patients result from an increase in the secretion of ANPs, which is probably accelerated by elevation of right or left atrial pressure, and that plasma concentrations of cGMP reflect circulating levels of α-hANP.

Published
1987
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47. -131-A STUDY ON FRANK STARLING CURVES CONTSRUCTED IN HUMANS

Author

Sato, Hiroshi, primary, Iizuka, Masahiko, additional, Kohmoto, Osami, additional, Mochizuki, Takatoshi, additional, Takahashi, Toshiyuki, additional, Sugimoto, Tokuichiro, additional, Ohya, Tetsuo, additional, Hirata, Yasunobu, additional, Serizawa, Takashi, additional, Ishii, Masao, additional, and Sugimoto, Tsuneaki, additional

Published
1986
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