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Biomedical subjects

Michiaki Yamakage

Publications and source records attributed to Michiaki Yamakage.

At least 19 recordsLinked to original sources
PubMed2006

Anandamide absorption by direct hemoperfusion with polymixin B-immobilized fiber improves the prognosis and organ failure assessment score in patients with sepsis.

PURPOSE: Direct hemoperfusion (DHP) with polymixin B-immobilized fiber (PMX) has been reported to be effective for patients with septic shock. The aim of this study was to clarify the mechanism of PMX-DHP effect on septic shock. METHODS: The following parameters were measured in septic shock patients who were treated with PMX-DHP: survival rate, sepsis-related organ failure assessment (SOFA) score, acute physiology and chronic health evaluation II (APACHE-II) score, and plasma concentrations of cannabinoids [anandamide (ANA) and 2-arachidonyl glyceride (2-AG)], cytokines [interleukin (IL)-6, IL-8, IL-10], transforming growth factor beta (TGF-beta), and calcitonin gene-related peptide (CGRP)]. The primary end point was mortality from all causes at day 28 after intensive care unit (ICU) admission or discharge. RESULTS: The survival rate of all patients at 28 days after ICU admission was 37.5% (9/24). The survival group showed significantly lower SOFA and APACHE-II scores than the nonsurvival group after PMX-DHP treatment (P = 0.008 and 0.028, respectively). The improved SOFA score group showed a better survival rate than the nonimproved SOFA score group (71.4% versus 23.5%, P = 0.028). Plasma ANA level significantly decreased after PMX-DHP treatment both in the improved SOFA score group and in the survival group. The level of 2-AG, however, showed no significant change in either group. CONCLUSION: ANA, an intrinsic cannabinoid that induces hypotension in septic shock, is inferred to be the main mechanism of the PMX-DHP effect. Removal of ANA by PMX-DHP could be key to successful septic shock treatment.

APACHE↗
PubMed2006

Preferable inotropic action of procaterol, a potent bronchodilator, on impaired diaphragmatic contractility in an intraabdominal septic model.

Intraabdominal sepsis can lead to acute respiratory failure, and concomitant diaphragmatic dysfunction may be aggravated by sepsis-induced airway hyperreactivity. We previously reported that isoproterenol, a nonselective beta-adrenoceptor agonist, increased diaphragmatic contractility and accelerated recovery from fatigue during sepsis. The purpose of this study was to demonstrate the direct inotropic effect of a potent bronchodilator and beta(2)-selective adrenoceptor agonist, procaterol, on fatigued diaphragmatic contractility in an intraabdominal septic model. Rats were divided into two groups: a cecal ligation and perforation (CLP) group and a sham group. CLP was performed in the CLP group whereas laparotomy alone was performed in the sham group. The left hemidiaphragm was removed at 16 h after the operation. The diaphragmatic tissues were exposed to procaterol (10(-8)-10(-6) M), and muscle contractility was assessed. Intracellular cyclic AMP levels were also measured in the CLP model. Procaterol caused an upward shift in the force-frequency curves in the CLP group whereas it had no effect on the curves in the sham group. Procaterol significantly increased cyclic AMP levels in the CLP model. We conclude that the potent bronchodilator procaterol had a direct and positive inotropic effect on the diaphragm in an intraabdominal septic model.

Adrenergic beta-Antagonists↗
PubMed2006

Different inhibitory effects of sevoflurane on hyperreactive airway smooth muscle contractility in ovalbumin-sensitized and chronic cigarette-smoking guinea pig models.

BACKGROUND: The authors hypothesized that sevoflurane had different inhibitory effects on hyperreactive airway smooth muscle contractility in different types of hyperreactive airway models. METHODS: The effects of sevoflurane on hyperreactive airways in ovalbumin-sensitized and chronic cigarette-smoking guinea pig models were investigated by measuring (1) total lung resistance, (2) smooth muscle tension and intracellular concentration of free Ca, (3) voltage-dependent Ca channel activity, and (4) cyclic adenosine monophosphate levels. RESULTS: Ovalbumin and muscarinic airway hyperreactivity was seen in ovalbumin-sensitized animals. Enlarged alveolar ducts/alveoli and lesser muscarinic hyperreactivity were observed in chronic cigarette-smoke animals. Although sevoflurane inhibited the acetylcholine-induced increase in total lung resistance in the control and ovalbumin-sensitized models, the anesthetic had a smaller effect in the chronic cigarette-smoking model. Similarly, in the chronic cigarette-smoking model, sevoflurane had a smaller inhibitory effect on carbachol-induced muscle contraction and increase in intracellular concentration of free Ca. Sevoflurane also had a smaller inhibitory effect on voltage-dependent Ca channel activity in the chronic cigarette-smoking group than in the other two groups. The sevoflurane-induced increase in cyclic adenosine monophosphate that was seen in the control and ovalbumin-sensitized groups was significantly suppressed in the chronic cigarette-smoking group. CONCLUSIONS: Although sevoflurane potently inhibited airway contractility in control and ovalbumin-sensitized models, the anesthetic had a smaller effect in a chronic cigarette-smoking model. The different inhibitory effects of sevoflurane on airway contractility depend, at least in part, on different effects on voltage-dependent Ca channel activity and cyclic adenosine monophosphate level.

Airway Resistance↗
PubMed2006

Effects of the Chinese herbal medicines Bupleuri radix, Ginseng radix, and Zingiberis rhizoma on lymphatic vessel activity in rats.

The aim of the present study was to determine the effects of the Chinese herbal medicines Bupleuri radix, Ginseng radix and Zingiberis rhizoma on spontaneous lymphatic vessel activity. The effect of each herbal medicine on in vivo lymphatic flow was examined by injection of dye into the femoral regions of rats after feeding with the herbal medicines. In an in vitro study, spontaneous changes in diameter of the rat thoracic duct were monitored, and each segment was exposed to each herbal medicine. In the in vivo study, 100% of the right iliac lymphatic node were positively stained in the herbal medicine group, whereas only 40% of the node were positively stained in the control group. In the in vitro study, Bupleuri radix and Ginseng radix increased the amplitude of spontaneous activity of lymphatic vessels in a concentration-dependent manner with or without L-NAME, an NO synthase inhibitor. The results indicated that the herbal medicines Bupleuri radix and Ginseng radix activated spontaneous lymphatic vasomotion and lymph flow, and the mechanisms of this effect seem to be independent of endothelial cells.

Animals↗
PubMed2006

[Intraoperative cardiac arrest due to coronary vasospasm after tourniquet release--a case report].

A 55-year-old man with no past history of ischemic heart disease underwent open reduction and internal fixation of the right arm because of an open fracture. Under general anesthesia with brachial plexus block, the operation was started after the upper arm had been pressurized at 280 mmHg by tourniquet. The patient had cardiac arrest 15 min after the tourniquet release, and was resuscitated by CPR. Postoperative intracoronary infusion of acetylcholine revealed that the coronary artery is sensitive to the agent, indicating that the intraoperative cardiac arrest might have been due to coronary vasospasm. Although the similar case is rare, attention should be taken during the anesthetic management with the use of tourniquet.

Anesthesia, General↗
PubMed2005

Changes in concentrations of free propofol by modification of the solution.

UNLABELLED: Because free propofol is thought to be responsible for pain on injection, we investigated the changes in concentrations of free propofol by modifying two kinds of propofol products in a medium- and long-chain triglyceride (MCT/LCT) emulsion and in an LCT emulsion. The techniques used in this study were 1) mixing 2% lidocaine (10:1), 2) mixing 5% dextrose in acetated Ringer's solution to reduce pH (10:1), and 3) changing the temperature to 4 degrees , 20 degrees , and 36 degrees C. The propofol preparations were dialyzed for 24 h, and the receptor medium was analyzed using high-performance liquid chromatography. The concentration of free propofol in propofol MCT/LCT was significantly smaller by 30% than that in propofol LCT. Neither mixing lidocaine nor cooling reduced the concentrations of free propofol in both products, but the concentrations were reduced by a decrease in pH and by an increase in temperature. Because mixing lidocaine can induce instability in an emulsion of propofol and warming can rapidly induce microbial growth, injection of lidocaine before propofol administration is recommended to reduce the pain on injection. The concentrations of free propofol in propofol MCT/LCT were significantly smaller (by approximately 30%-45%) than those in propofol LCT during any situation in this study. IMPLICATIONS: Neither mixing lidocaine nor cooling reduced the concentrations of free propofol in both products but the concentrations were reduced by a decrease in pH and by an increase in temperature. Propofol medium- and long-chain triglycerides had significantly smaller concentrations by approximately 30%-45% than those in propofol long-chain triglycerides during any situation in this study.

Anesthetics, Intravenous↗
PubMed2005

[Evaluation by undergraduate medical students of clinical clerkships in the department of anesthesiology--comparison with the evaluation in previous fiscal year].

BACKGROUND: Clinical Clerkships in the Department of Anesthesiology were evaluated by undergraduate medical students and compared with other clinical departments and those of previous fiscal year 2003. METHODS: Questionnaire surveys by 5 step Likert measure were conducted to ask the students for the evaluation of each department or division, and formative evaluation was performed after the all clerkships. The questionnaire consisted of 12 questions on 1) orientation, 2) learning chances and provision of teaching materials, 3) feedback, learning promotion and teaching attitude, 4) coordination of human relationship between medical staff and students, and 5) overall evaluation of teacher's physician. RESULTS: The average score of our department was 4.40 (mean, 5 th grade of all 26 departments/divisions), and the score of the question on provision of medical practice (4.71) was the best among the all departments/divisions. The evaluation grading was rather low for the question on chance for physical examinations (3.80). CONCLUSIONS: Reevaluation of the educational program in our department based on the results of the survey is essential for improvement of the program, and further provision of chances, especially for physical examinations, is also needed for undergraduate students in the program by including palliative medical care program.

Anesthesiology↗
PubMed2005

[A trial of introduction of portfolio to elective clinical clerkship in anesthesiology].

BACKGROUND: Portfolio as one of the educational techniques was introduced to elective clinical clerkship (CC) of Anesthesiology in Sapporo Medical University School of Medicine in the 2003 fiscal year. METHODS: Fourteen medical students who elected Anesthesiology CC for 3 weeks had a duty to study and feed back their CC everyday by writing portfolio, and the attending checked and fed back their portfolio every week. At the end of the CC, questionnaire surveys by 5 step Likert measure and group discussion were conducted to determine the evaluation by students of the portfolio in Anesthesiology CC. RESULTS: The average score of the questionnaire surveys was high(4.78). However, the scores of usefulness of the portfolio for feedback to student's attitude and to good relationship among medical staff were relatively low (4.6 and 4.4, respectively). CONCLUSIONS: The use of a portfolio as a educational technique in elective CC seems to be useful, and further education to chief/senior medical staff for feedback to student's attitude and other kinds of educational techniques for feedback to good relationship among medical staff are needed.

Anesthesiology↗
PubMed2005

[Perioperative evaluation of a kit for simplified measurement of blood theophylline concentration (Accumeter Theophylline)].

BACKGROUND: We investigated the perioperative usefulness of a kit for simplified measurement of blood theophylline concentration (BTC), Accumeter theophylline (Nikken Chemicals Co.) in asthmatic patients. METHODS: Study 1) BTCs were measured by Accumeter at the beginning of surgery in asthmatic patients who had been medicated with oral theophylline. Study 2) BTCs were corrected during anesthesia in asthmatic patients who showed lower BTCs (<8 microg x g ml(-1)) at the beginning of surgery. Study 3) Theophylline was administered to asthmatic patients who had not been medicated with theophylline, and calculated and measured BTCs were compared. RESULTS: Study 1) Measured BTC at the begin- ning of surgery was 8.2 +/- 3.1 microg x ml(-1) (mean +/- SD), and 14 of 31 patients (45%) showed lower BTC. Patients who smoked showed a significantly lower BTC than that of non-smoking patients (P=0.04). Study 2) Five of 10 patients showed lower BTC at the beginning of surgery, but BTC had increased significantly at the end of surgery after i.v. administration of theophylline. Study 3) There was no significant linear correlation between calculated and measure BTCs after i.v. administration of theophylline (R2=0.25, n=10). Although the mean was near zero (0.05) by limits of agreement, 2 SD was large (2.53). There was no patient who showed wheezing during the study. CONCLUSIONS: It is important to monitor BTCs perioperatively in asthmatic patients, and Accumeter theophylline is a simple and useful device for management of BTC.

Adolescent↗
PubMed2004

Single-channel activity of L-type Ca2+ channels reconstituted with the beta2c subunit cloned from the rat heart.

We recently cloned the beta(2c) subunit of the L-type Ca(2+) channel as a functional type of beta subunit from the rat heart. In order to clarify the contribution of the beta(2c) subunit to native Ca(2+) channel function, we investigated the single-channel properties of Ca(2+) channels reconstituted with beta(2a) or beta(2c) subunits and compared them with the properties of native channels. In contrast to the Ca(2+) channel with beta(2a) subunit, long-lasting closings were dominant in the Ca(2+) channel with beta(2c) subunit and the native channel. The ensemble-averaged current of the cells with beta(2c) subunits was comparable to that of the native cardiomyocytes. Many high P(o) sweeps (mode 2) were observed in the cells with beta(2a) subunits, while only a few high P(o) sweeps were observed in the cells with beta(2c) subunits and the native cells. These findings suggest that the beta(2c) subunit is one of the functional beta subunits in the rat heart.

3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗
PubMed2004

Safety and beneficial effect on body core temperature of a prewarmed plasma substitute--hydroxyethyl starch--during anesthesia.

PURPOSE: We investigated, first, the safety of use and stability of a plasma substitute-hydroxyethyl starch (HES)-kept in a warming cabinet for a long period, and then the effect on body core temperature of the prewarmed HES in patients during urological surgery. METHODS: In the first part of the study, HES colloid solutions (500 ml per pack; Hespander) were kept in a warming cabinet (40 degrees C) for 3 months and were tested for biological and chemical safety and stability. In the second part of the study, 1000 ml of HES at room temperature (control group; n = 10) or kept in a warming cabinet for a few days (warmed group; n = 10) was infused via a central venous catheter for 30 min in patients undergoing urological surgery under general anesthesia with lumbar epidural anesthesia. Esophageal temperature was monitored as the core temperature. HES fluid temperatures in the pack and at the end of a 1-m intravenous tube connected to the central venous catheter were also measured. RESULTS: The test of HES products warmed for 3 months passed all inspections performed during the study period. In the warmed group, the pack and intravenous tube temperatures of HES were still high at 15 min after infusion (37.1 degrees +/- 1.5 degrees C [mean +/- SD] and 34.8 degrees +/- 2.2 degrees C, respectively). Core temperature in the warmed group decreased significantly, by 0.34 degrees +/- 0.06 degrees C, but was significantly higher than that in the control group (by 0.84 degrees +/- 0.13 degrees C) after 30 min of the infusion. CONCLUSIONS: The use of HES products kept in a warming cabinet prior to surgery can maintain warm body temperature, easily, safely, and effectively.

Aged↗
PubMed2004

Effects of oral atenolol on volatile anesthetic induction with sevoflurane in adults.

PURPOSE: To determine whether premedication with a beta-blocker can bring about a more rapid and smooth induction of anesthesia, we investigated the effect of oral premedication with atenolol on volatile anesthetic induction with sevoflurane by monitoring the cardiac output (CO) and bispectral (BIS) index. METHODS: Twenty-four patients undergoing general anesthesia with endotracheal intubation were randomly divided into two groups: a control group ( n = 12) and a beta-blocker group ( n = 12). Each patient in the beta-blocker group was premedicated with oral atenolol 25 mg 1 h before the induction of anesthesia. Anesthesia was induced by the repeated vital capacity technique with 5% sevoflurane and 66% nitrous oxide. The trachea was intubated 5 min after sevoflurane exposure. The CO and BIS index, as well as the induction time and specific side effects of induction (e.g., movement of limbs), were recorded. RESULTS: There were no significant differences in induction time and specific side effects between the groups. The downward-sloping part of the BIS index curve in the beta-blocker group (mean, 2.9 +/- 0.2) was significantly sharper than that in the control group (2.5 +/- 0.2), and the BIS index after induction of anesthesia was significantly lower in the beta-blocker group (21.0 +/- 2.2) than in the control group (24.2 +/- 2.0). CO in the beta-blocker group was significantly lower than in the control group during the study period. The hemodynamic changes caused by endotracheal intubation were inhibited in the beta-blocker group but not in the control group. CONCLUSION: Oral premedication with 25 mg of atenolol provides a more rapid decrease in BIS index and is recommended for use in stable volatile anesthetic induction with sevoflurane.

Administration, Oral↗
PubMed2004

Inhibitory effects of the anesthetics propofol and sevoflurane on spontaneous lymphatic vessel activity in rats.

BACKGROUND: The effects of propofol and sevoflurane on lymphatic vessel activity are unknown. This study aimed to clarify the effects of these anesthetics on lymphatic vessel activity in rats by the use of a technique for mechanical removal of the endothelium. METHODS: The authors first examined the effects of propofol (8 mg/kg) and sevoflurane (2.0%) on in vivo lymphatic flow by injection of dye into the femoral regions of rats. In the in vitro study, the ends of the vessel segments of rat thoracic duct were connected to a syringe and stopcock, respectively. Spontaneous changes in diameter of each segment were monitored, and the extraluminal side of each segment was exposed to propofol (1 x 10(-6) approximately 3 x 10(-5) M) or sevoflurane (0.5 approximately 2.0%). Endothelial function was eliminated by perfusion of air into the lumen. RESULTS: In the dye uptake study, 80% of iliac lymphatic nodes were positively stained in a control group, whereas only 10% and 20% were positively stained in propofol and sevoflurane groups, respectively. In the in vitro study, both of the anesthetics significantly decreased the amplitude of spontaneous activity of lymphatic vessels with or without endothelial function. Sevoflurane inhibited the frequency of lymphatic vessel activity but propofol had no effect on it. When the endothelial function was eliminated, both anesthetics decreased the frequency of spontaneous activity of lymphatic vessels. CONCLUSIONS: Propofol and sevoflurane seem to have some different effects on endothelial function, which regulates the pacemaking of spontaneous contraction of lymphatic vessels.

Acetylcholine↗
PubMed2004

[Intravenous fluid administration and management of body temperature].

Hypothermia occurs due to body heat redistribution between core and peripheral tissues as well as imbalance between heat loss and production. Perioperative hypothermia not only induces offensive shivering and prolongation of anesthetic recovery but also increases blood loss and incidence of surgical wound infection, increasing postoperative morbidity. It has been shown that intraoperative intravenous fluid administration and blood product transfusion have considerable effects on body temperature. Thus, it is important to monitor and control the temperature of fluids. Anesthesiologists should have knowledge of the characteristics of the various kinds of fluid warmer currently available and use them appropriately according to surgical procedures and the patient's position. It was reported recently that administration of amino acid can prevent intraoperative hypothermia, possibly by increasing the heat production in the body.

Amino Acids↗
PubMed2004

[Coronary artery spasm during cholecystectomy with pneumoperitoneum--a case report].

A 59-year-old man without a history of ischemic heart disease underwent elective laparoscopic cholecystectomy under general anesthesia with epidural anesthesia. About 15 min after pneumoperitoneum had been achieved, the patient developed ST elevation and hypotension. Vagal stimulation resulting from stretching peritoneum, the procedure and epidural anesthesia are thought to have induced vasospasm. The ST segment became normal after interruption of CO2 insufflation. A postoperative coronary artery angiogram showed normal coronary arteries, but diffuse coronary artery spasm was seen after intracoronary injection of acetylcholine. The patient was discharged on nitrates. Patients with gall bladder stones sometimes have coronary risk factors of obesity, hyperlipidemia and hyperglycemia. Careful attention should also be given to patients who do not have a history of coronary disease.

Anesthesia, Epidural↗
PubMed2004

[Evaluation by undergraduate medical students of clinical clerkships in the Department of Anesthesiology].

BACKGROUND: Clerkships for undergraduate clinical training were introduced in Sapporo Medical University School of Medicine in 2002. METHODS: Questionnaire surveys by 5 steps Likert measure were conducted by asking the students about the evaluation of each department or division, and overall evaluation was obtained after the clerkships. The questionnaire consisted of 12 questions on 1) orientation; 2) learning chances and provision of teaching materials; 3) feedback, learning promotion and teaching attitude; 4) coordination of human relationship between medical staff and students; and 5) overall evaluation of teacher's physician. RESULTS: The average score for our department was 4.30 (mean, 6th grade of all 26 departments/divisions), and the scores on provision of medical practice (4.69) and the overall teacher's physician grading (4.65) were the best among the all departments/divisions. The evaluation gradings were rather low on chances for medical and health care interviews (3.59); physical examinations (3.83); and description of medical record (3.73). CONCLUSIONS: Reevaluation of the educational program in our department based on the results of the survey is essential for improvement of the program, and further provision of chances, especially for medical interviews, physical examinations and description of medical record is also needed for undergraduate students in the program.

Anesthesiology↗