Details of a Researcher - YAMAKAGE Michiaki

Misc - YAMAKAGE Michiaki

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Equipments for body temperature monitoring

Perioperative monitoring equipments 2003

Preoperative evaluation and perioperative management of patients with pulmonary emphysema

Life Support and Anesthesia 10 216 - 220 2003

成人の導入法の工夫

今日から実践できるVIMA 2003

麻酔・手術と血小板・血液凝固能

臨床麻酔 27 351 - 364 2003

Cardiac pacemaker and Anesthesia

Life Support and Anesthesia 10 750 - 753 2003

最近の医学教育の変遷と動向

札幌医学雑誌 72 37 - 48 2003

Keynote, iMovie, iDVD

Nice presentation for everyone 2003

周術期体温に関する基礎知識

山蔭道明

日本臨床麻酔学会誌 = The Journal of Japan Society for Clinical Anesthesia 22 ( 8 ) S130 - S131 2002.09

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Prophylactic IM small-dose phenylephrine blunts spinal anesthesia-induced hypotensive response during surgical repair of hip fracture in the elderly

K Nishikawa, M Yamakage, K Omote, A Namiki

ANESTHESIA AND ANALGESIA ( LIPPINCOTT WILLIAMS & WILKINS ) 95 ( 3 ) 751 - 756 2002.09

In a double-blinded, placebo-controlled, randomized study, we evaluated the effect of prophylactic IM phenylephrine at doses of 1.5 and 3 mg on hyperbaric tetracaine spinal anesthesia-induced hypotension in 90 normotensive and hypertensive patients aged >65 yr undergoing surgery for hip fracture. Thirty normotensive patients received 1.5 or 3 mg of phenylephrine IM (N/P-1.5 and N/P-3.0 groups; n = 15 in each), whereas controls received saline (N/C group; n = 15), and 45 hypertensive patients were treated in a similar manner (H/P-1.5, H/P-3.0, and H/C groups; n = 15 in each). All groups had a peak sensory block height of T9, with a range of T8 to T10. The incidence of hypotension (>25% decrease in mean arterial blood pressure [MAP] from baseline) was significantly lower in the patients who received phenylephrine 1.5 or 3 mg than in the controls, both in the normotensive and hypertensive groups (P < 0.01). The N/P-3.0 and N/P-1.5 groups and the H/P-3.0 group had significantly lower percentage reductions in MAP (P < 0.05) and required significantly smaller doses of rescue IV ephedrine (P < 0.05) than did the N/C group or the H/C group. The H/P-1.5 group also required significantly less rescue IV ephedrine (P < 0.05), although it was not sufficient to significantly attenuate the percentage decrease in MAP compared with that in the H/C group. Bradycardia (heart rate <50 bpm) as an adverse effect after IM administration of phenylephrine was not observed in any of the groups. Hypertension (MAP >20% increase from baseline) after medication occurred in the N/P-3.0 and H/P-3.0 groups, but not in the N/P-1.5 and H/P-1.5 groups. We conclude that prophylactic IM injection of 1.5 mg of phenylephrine is a safe (defined as the inhibition of bradycardia and hypertension) and effective means of reducing the incidence of hypotension associated with spinal anesthesia in normotensive and hypertensive elderly patients.

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Inhibitory effects of volatile anesthetics on currents produced on heterologous expresssion of KvLQT1 and minK in Xenopus oocytes

XD Chen, M Yamakage, Y Yamada, N Tohse, A Namiki

VASCULAR PHARMACOLOGY ( ELSEVIER SCIENCE INC ) 39 ( 1-2 ) 33 - 38 2002.07

The slowly activating component of delayed rectifier K+ current (I-Ks) in the heart modulates the repolarization of cardiac action potential. We investigated the effects of the volatile anesthetics isoflurane and sevoflurane on cloned I-Ks coexpressed by KvLQTI and minK. Currents were induced following injection into oocytes of KvLQTI mRNA (10 ng) with or without minK mRNA (I ng), which were transcribed in vitro from cDNAs of normal rats hearts. A two-electrode voltage-clamp recording technique was used to investigate the effects of isoflurane (0-1.5 minimum alveolar concentration, MAC) and sevoflurane (0-1.5 MAC) on I-Ks (KvLQTI with minK) and KvLQTI alone currents. Currents were activated by step depolarizations to a series of potentials from a holding potential of -80 mV and measured as the deactivating tail current on repolarization to -60 mV. Following a 2-s depolarization to 40 mV, isoflurane and sevoflurane caused potency-dependent reductions in I-Ks and KvLQTI currents. Both of the volatile anesthetics tested accelerated the deactivation of I-Ks and KvLQTI currents. We conclude that the significant inhibitory effect of volatile anesthetics on the cloned I-Ks may partly contribute to the clinical observations of the prolongation of the ventricular repolarization (Q-T interval) by the anesthetics. (C) 2002 Elsevier Science Inc. All rights reserved.

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A truncated splice variant of KCNQ1 cloned from rat heart

Y Yamada, XD Chen, T Kobayashi, Y Kamada, M Nagashima, M Tsutsuura, S Seki, M Yamakage, A Namiki, N Tohse

BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS ( ACADEMIC PRESS INC ELSEVIER SCIENCE ) 294 ( 2 ) 199 - 204 2002.06

KCNQ1 encodes a pore-forming subunit of potassium channels. Mutations in this gene cause inherited diseases, i.e., Romano-Ward syndrome and Jervell and Lange-Nielsen syndrome. A truncated isoform of KCNQ1 was reported to be expressed physiologically and to suppress a delayed rectifier potassium current dominant-negatively in human heart. However, it is not known whether this way of modulation occurs in other species. We cloned another truncated splice variant of KCNQ1 (tr-rKCNQ1) from rat heart. Judging from the deleted sequence of the tr-rKCNQ1, the genomic structure of rat in this portion might be different from those of human and mouse. Otherwise, an unknown exon might exist. RT-PCR analysis demonstrated that the tr-rKCNQ1 was expressed in fetal and neonatal hearts. When this gene was expressed along with a full-length KCNQ1, it suppressed potassium currents, whether a regulatory subunit minK was co-expressed or not. (C) 2002 Elsevier Science (USA). All rights reserved.

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Editorial II - Effects of anaesthetic agents on airway smooth muscles

M Yamakage

BRITISH JOURNAL OF ANAESTHESIA ( OXFORD UNIV PRESS ) 88 ( 5 ) 624 - U2 2002.05

Other

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Intermittent pneumatic compression prevents venous stasis in the lower extremities in the lithotomy position

S Kohro, M Yamakage, T Takahashi, M Kondo, K Ota, A Namiki

CANADIAN JOURNAL OF ANAESTHESIA-JOURNAL CANADIEN D ANESTHESIE ( CANADIAN ANESTHESIOLOGISTS SOC ) 49 ( 2 ) 144 - 147 2002.02

Purpose: To investigate the interactions of a new lithotomy positioning device (LPD) with two intermittent pneumatic compression (IPC) devices by measuring femoral venous flow velocity. Methods: Subjects were divided into three groups: 1) supine position as a control, 2) lithotomy position using a conventional LPD, and 3) lithotomy position using a new LPD, Levitator(TM), These three groups were further divided in two according to the type of IPC device used: AV-impulse(TM) (rapid IPC) and SeQuel(TM) (standard IPC). Peak femoral venous flow velocity was measured by using an ultrasonic echo diagnostic device. Data were analyzed by one-way ANOVA with Fisher's test or by the unpaired two-tailed t test. Results: Moving to the conventional lithotomy position from the supine position, venous flow velocity was decreased by 38% in both IPC device groups. Even when the new LPD was used to support the lithotomy position, the flow velocity was decreased by 24%, but the velocity was significantly higher than in the conventional lithotomy position. Both rapid and standard IPC devices increased flow velocity to 77% and 107% (first compression) and to 71 % and 84% (fifth compression) of the control values during compression, respectively. In the lithotomy position group using the new LPD, similar increases in flow were seen with the use of IPC devices. Conclusion: Both rapid and standard IPC devices are useful for maintaining venous flow of the lower extremities in the lithotomy position.

Inhibitory effects of volatile anesthetics on K+ and Cl- channel currents in porcine tracheal and bronchial smooth muscle

XD Chen, M Yamakage, A Namiki

ANESTHESIOLOGY ( LIPPINCOTT WILLIAMS & WILKINS ) 96 ( 2 ) 458 - 466 2002.02

Background. K+ and Ca2+-activated Cl- (Cl-Ca) channel currents have been shown to contribute to the alteration of membrane electrical activity in airway smooth muscle. This study was conducted to investigate the effects of volatile anesthetics, which are potent bronchodilators, on the activities of these channels in porcine tracheal and bronchial smooth muscles. Methods: Whole-cell patch clamp recording techniques were used to investigate the effects of superfused isoflurane (0-1.5 minimum alveolar concentration) or sevoflurane (0-1.5 minimum alveolar concentration) on K+ and Clue channel currents in dispersed smooth muscle cells. Results: Isoflurane and sevoflurane inhibited whole-cell K+ currents to a greater degree in tracheal versus bronchial smooth muscle cells. More than 60% of the total K+ currents in tracheal smooth muscle appeared to be mediated through delayed rectifier K+ channels compared with less than 40% in bronchial smooth muscle. The inhibitory effects of the anesthetics were greater on the delayed rectifier K+ channels than on the remaining K+ channels. Cl- currents through Cl-Ca channels were significantly inhibited by the anesthetics. The inhibitory potencies of the anesthetics on the Clue channels were not different in tracheal and bronchial smooth muscle cells. Conclusions: Volatile anesthetics isoflurane and sevoflurane significantly inhibited Cl- currents through Cl-Ca channels, and the inhibitory effect is consistent with the relaxant effect of volatile anesthetics in airway smooth muscle. Different distributions and different anesthetic sensitivities of K+ channel subtypes could play a role in the different inhibitory effects of the anesthetics on tracheal and bronchial smooth muscle contractions.

Calcium channels - basic aspects of their structure, function and gene encoding; anesthetic action on the channels - a review

M Yamakage, A Namiki

CANADIAN JOURNAL OF ANAESTHESIA-JOURNAL CANADIEN D ANESTHESIE ( CANADIAN ANESTHESIOLOGISTS SOC ) 49 ( 2 ) 151 - 164 2002.02

Book review, literature introduction, etc.

Purpose: To review recent findings concerning Call channel subtype/structure/function from electrophysiological and molecular biological studies and to explain Ca2+ channel diseases and the actions of anesthetics on Ca2+ channels. Source: The information was obtained from articles published recently and from our published work. Principal findings: Voltage-dependent Ca2+ channels serve as one of the important mechanisms for Ca2+ influx into the cells, enabling the regulation of intracellular concentration of free Ca2+, Recent advances both in electrophysiology and in molecular biology have made it possible to observe channel activity directly and to investigate channel functions at molecular levels, The Ca2+ channel can be divided into subtypes according to electrophysiological characteristics, and each subtype has its own gene. The L-type Ca2+ channel is the target of a large number of clinically important drugs, especially dihydropyridines, and binding sites of Ca2+ antagonists have been clarified. The effects of various kinds of anesthetics in a variety of cell types have been demonstrated, and some clinical effects of anesthetics can be explained by the effects on Ca2+ channels. It has recently become apparent that some hereditary diseases such as hypokalemic periodic paralysis result from calcium channelopathies. Conclusion: Recent advances both in electrophysiology and in molecular biology have made it possible to clarify the Ca2+ channel structures, functions, genes, and the anesthetic actions on the channels in detail. The effects of anesthetics on the Ca2+ channels either of patients with hereditary channelopathies or using gene mutation techniques are left to be discovered.

Sevoflurane inhibits contraction of uterine smooth muscle from pregnant rats similarly to halothane and isoflurane

M Yamakage, N Tsujiguchi, XD Chen, Y Kamada, A Namiki

CANADIAN JOURNAL OF ANAESTHESIA-JOURNAL CANADIEN D ANESTHESIE ( CANADIAN ANESTHESIOLOGISTS SOC ) 49 ( 1 ) 62 - 66 2002.01

Purpose: The present study was designed to clarify the direct effects of the volatile anesthetics halothane, isoflurane and sevoflurane on oxytocin-induced uterine smooth muscle contraction from pregnant rats. Methods: Longitudinal smooth muscle layers were obtained from pregnant rats. Intracellular concentration of free Ca++ ([Ca++](i)) was measured, using a fluorescence technique, simultaneously with muscle tension. Inward Ba++ current (I-Ba) through voltage-dependent Ca++ channels (VDCCs) was measured using a whole cell patch clamp technique. After incubation with 20 nM oxytocin, halothane, isoflurane or sevoflurane (1, 2, and 3%) was introduced into the tissue bath. Results: Ail volatile anesthetics significantly inhibited muscle contraction concomitant with a decrease in [Ca++](i). Volatile anesthetics also inhibited the peak I-Ba, When the anesthetic concentrations were expressed as multiples of minimum alveolar concentrations, there were no differences in the inhibitory potencies of the three volatile agents tested for muscle tension and VDCC. Conclusions: Volatile anesthetics halothane, isoflurane and sevoflurane reduce the oxytocin-induced contraction of pregnant uterine smooth muscle. Inhibition of the contraction by the volatile anesthetics is due, at least in part, to the decrease in [Ca++](i) and the decrease in [Ca++](i) may be mediated by inhibition of VDCC activity.

The repolarizing effects of volatile anesthetics on porcine tracheal and bronchial smooth muscle cells

M Yamakage, XD Chen, A Kimura, S Iwasaki, A Namiki

ANESTHESIA AND ANALGESIA ( LIPPINCOTT WILLIAMS & WILKINS ) 94 ( 1 ) 84 - 88 2002.01

This study was conducted to determine the effects of volatile anesthetics (potent bronchodilators) on membrane potentials in porcine tracheal and bronchial smooth muscle cells. We used a current-clamp technique to examine the effects of the volatile anesthetics isoflurane (1.5 minimum alveolar anesthetic concentration [MAC]) and sevoflurane (1.5 MAC) on membrane potentials of porcine tracheal and bronchial (third- to fifth-generation) smooth muscle cells depolarized by a muscarinic agonist, carbachol (1 muM). The effects of volatile anesthetics on muscarinic receptor binding affinity were also investigated by using a radiolabeled receptor assay technique. The volatile anesthetics isoflurane and sevoflurane induced significant repolarization of the depolarized cell membranes in the trachea (from -19.8 to -23.6 mV and to -24.8 mV, respectively) and bronchus (from -24.7 to -29.3 mV and -30.4 mV, respectively) without affecting carbachol binding affinity to the muscarinic receptor, The repolarizing effect was abolished by a Ca2+-activated Cl- channel blocker, niflumic acid. These results indicate that volatile anesthetic-induced repolarization of airway smooth muscle cell membranes might be caused by a change in Ca2+-activated Cl channel activity and that the different repolarized effects of the volatile anesthetics could in part contribute to the different effects of volatile anesthetics on tracheal and bronchial smooth muscle contractions.

Usefulness of oral hypnotic premedication for volatile induction of anesthesia in adults

Michiaki Yamakage, Shigeo Tsuchiya, Naomi Ohtsuka, Sohshi Iwasaki, Akiyoshi Namiki

Journal of Anesthesia 16 ( 3 ) 194 - 197 2002

Purpose. We investigated the effects of oral hypnotic premedication for smooth anesthetic induction and for the patient's comfort under anesthesia, using sevoflurane without nitrous oxide. Methods. Adult patients were divided into four groups: control (n = 12), triazolam (0.25mg n = 12), zopiclone (7.5mg n = 12), and clonidine (0.15mg n = 12) groups. Each premedication was given to each patient 1 h before the anesthesia. The patients breathed out to residual volume and then the anesthetic mask was fitted. The repeated vital capacity breathing technique was used, with 5% sevoflurane in 101·min-1 oxygen. Induction time, specific induction side effects, and acceptability of this technique by the patients were recorded by an independent observer. Results. Induction time in the premedicated groups ranged from 66 ± 12s (mean ± SD) to 76 ± 14s, and these values were significantly shorter than that in the control group (92 ± 16s). The number of patients in whom adverse effects occurred during anesthetic induction was significantly greater in the control group (4 patients 33%) than in the premedicated groups (1 patient each 8%). Acceptability of the smell of sevoflurane was significantly higher in the premedicated groups (8-10 patients 67%-83%) than in the control group (5 patients 42%). Conclusion. Oral hypnotic premedications with either triazolam (0.25 mg), zopiclone (7.5 mg), or clonidine (0.15 mg) are recommended for smoother volatile anesthetic induction and for the patient's comfort in adults.

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Evaluation of four techniques of warming intravenous fluids

Naomi Ohtsuka, Michiaki Yamakage, Xiangdong Chen, Yasuhiro Kamada, Akiyoshi Namiki

Journal of Anesthesia 16 ( 2 ) 145 - 149 2002

Purpose. This study was conducted to compare the fluid warming capabilities at different flow rates in four different warming systems. Methods. The intravenous (IV) fluid warmers used in this study were a water-bath warmer, a forced-air warmer, a dry-heat plate warmer, and an IV fluid tube warmer. Ringer's solution at room temperature or at ice-cold temperature (120-3000 ml·h-1) was used as an IV fluid, and the IV fluid temperatures were measured with thermocouples at the end of a 1-m tube connected to the warmer. Results. The temperature of the IV fluid delivered by the water bath and the forced-air warming system increased as the flow rate increased up to 1200 ml·h-1 but decreased with further increase of the flow rate. The temperature of the IV fluid delivered by the dry-heat plate warmer significantly increased as the flow rate increased within the range studied. The delivered temperature did not depend on the flow rate within the range studied when the IV fluid tube warmer was used. Conclusion. It is important to choose a warmer according to its characteristics as well as its performance.

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Topics related to tabacco

YAMAKAGE M

J Clin Anesth (Jpn) 24 641 - 651 2002

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