Biomedical subjects

S Kohro

Publications and source records attributed to S Kohro.

17 recordsLinked to original sources

PubMed2005

Intermittent pneumatic foot compression can activate blood fibrinolysis without changes in blood coagulability and platelet activation.

BACKGROUND: Intermittent pneumatic foot compression (IPC) is a useful technique for prophylaxis of peri-operative venous thromboembolism. The aim of this study was to determine the effect of IPC on blood coagulation/fibrinolysis and platelet function using a blood viscometer (Sonoclot) and a platelet aggregation monitor (WBA analyzer(TM)), respectively. Using the same blood samples, serum levels of tissue-type plasminogen activator (t-PA), thrombomodulin (TM) and activated protein C (APC) were also measured. METHODS: The soles and legs of each subject (n = 8) were compressed for 3 s (130 mmHg) at a 0.3-Hz interval using an IPC device. Parameters were measured 2 min before and at the end of 60-min compression. RESULTS: Parameters of the Sonoclot time-to-peak were shortened and clot retraction rate was increased significantly by IPC, whereas the other parameters did not change. These results indicate that IPC can activate blood fibrinolysis but not coagulability. A parameter of the WBA analyzer PATI (platelet aggregatory threshold index) did not change, indicating that IPC cannot activate platelet function per se. The concentration of t-PA decreased slightly but significantly. A decrease in the concentration of t-PA can lead to activation of fibrinolysis. Other humoral parameters did not change, indicating that IPC has no effect on endothelial function. Although neither blood coagulability nor platelet function were affected by IPC, fibrinolytic activity increased slightly, probably by activation of t-PA function. CONCLUSION: IPC is useful for prophylaxis for thromboembolism by activation of blood fibrinolysis as well as inhibition of blood stasis.

Activated Protein C Resistance↗

PubMed2004

Reductions in levels of bacterial superantigens/cannabinoids by plasma exchange in a patient with severe toxic shock syndrome.

Toxic shock syndrome is a rare but potentially fatal toxin-mediated febrile illness. We report a case of toxic shock syndrome complicated by life-threatening organ dysfunction with high toxin-1 and staphylococcus enterotoxin type A levels that were successfully reduced by early introduction of plasma exchanges. The report shows the time course of the concentrations of anandamide and 2-arachidonyl glyceride and confirms that early introduction of plasma exchange can result in a rapid reduction of circulating toxins and mediators in the treatment of life-threatening multiple organ dysfunction.

Adolescent↗

PubMed2001

Anesthetic effects on mitochondrial ATP-sensitive K channel.

BACKGROUND: Volatile anesthetics show an ischemic preconditioning-like cardioprotective effect, whereas intravenous anesthetics have cardioprotective effects for ischemic-reperfusion injury. Although recent evidence suggests that mitochondrial adenosine triphosphate-regulated potassium (mitoK(ATP)) channels are important in cardiac preconditioning, the effect of anesthetics on mitoK(ATP) is unexplored. Therefore, the authors tested the hypothesis that anesthetics act on the mitoK(ATP) channel and mitochondrial flavoprotein oxidation. METHODS: Myocardial cells were isolated from adult guinea pigs. Endogenous mitochondrial flavoprotein fluorescence, an indicator of mitochondrial flavoprotein oxidation, was monitored with fluorescence microscopy while myocytes were exposed individually for 15 min to isoflurane, sevoflurane, propofol, and pentobarbital. The authors further investigated the effect of 5-hydroxydeanoate, a specific mitoK(ATP) channel antagonist, on isoflurane- and sevoflurane-induced flavoprotein oxidation. Additionally, the effects of propofol and pentobarbital on isoflurane-induced flavoprotein oxidation were measured. RESULTS: Isoflurane and sevoflurane induced dose-dependent increases in flavoprotein oxidation (isoflurane: R2 = 0.71, n = 50; sevoflurane: R2 = 0.86, n = 20). The fluorescence increase produced by both isoflurane and sevoflurane was eliminated by 5-hydroxydeanoate. Although propofol and pentobarbital showed no significant effects on flavoprotein oxidation, they both dose-dependently inhibited isoflurane-induced flavoprotein oxidation. CONCLUSIONS: Inhalational anesthetics induce flavoprotein oxidation through opening of the mitoK(ATP) channel. This may be an important mechanism contributing to anesthetic-induced preconditioning. Cardioprotective effects of intravenous anesthetics may not be dependent on flavoprotein oxidation, but the administration of propofol or pentobarbital may potentially inhibit the cardioprotective effect of inhalational anesthetics.

ATP-Binding Cassette Transporters↗

PubMed1999

In vitro effects of propofol on blood coagulability and fibrinolysis by the use of thromboelastograph technique.

BACKGROUND: To investigate the in vitro effects of propofol on blood coagulability and fibrinolysis by the use of thromboelastograph (TEG) technique. METHODS: The blood samples, obtained from 14 healthy volunteers, were divided into two groups: propofol (n = 7) and intralipid (n = 7), and 360 microliters volumes of whole blood were incubated with 2 microliters of 1% propofol and with its solvent intralipid, respectively. The incubated sample was then used for TEG measurements. RESULTS: The maximum amplitude (MA), which reflects coagulability, in the intralipid group significantly increased by about 7% and 16% compared to the control and propofol groups, respectively (P < 0.05), whereas the MA in the propofol group did not change. The fibrinolytic rate (FR) in the propofol group significantly increased by about 170% and 210% compared to the control and intralipid groups, respectively (P < 0.05), whereas the FR in the intralipid group did not change. CONCLUSIONS: Propofol, per se, has at the concentration of 55.6 micrograms.ml-1 an in vitro accelerative effect on blood fibrinolysis detected by TEG.

Anesthetics, Intravenous↗

PubMed1998

The usefulness of celite-activated thromboelastography for evaluation of fibrinolysis.

PURPOSE: Although thromboelastography is useful for measuring both coagulability and fibrinolysis, it takes about two hours to measure all parameters including fibrinolytic rate. The present study aimed to investigate the usefulness of celite-activated thromboelastography (TEGc) to evaluate fibrinolytic status in non-cardiac surgery. METHODS: Whole blood samples were obtained from 30 patients for non-cardiac surgery, and used for measurements of both native TEG (TEGn) and TEGc. The final concentration of 1% (w/v) celite was used for TEGc. RESULTS: Time for measurement of the fibrinolytic rate (FR) of TEGc in patients (56.7 +/- 4.0 min) was less than half that of FR of TEGn (123.3 +/- 15.6 min) (P < 0.05), suggesting a more rapid assessment of fibrinolytic status. A linear relationship was observed between FR values of TEGc and those of TEGn (r = 0.93, P < 0.0001), suggesting the usefulness of the fibrinolytic parameter of TEGc. CONCLUSION: TEGc is a useful technique for a more rapid assessment of fibrinolytic status.

Adult↗

PubMed1998

Surgical/tourniquet pain accelerates blood coagulability but not fibrinolysis.

Tissue damage during surgery induces coagulation factors and activates platelets. Surgical pain may provoke release of catecholamines, leading to hypercoagulability. We have investigated the effect of surgical pain on blood coagulability and fibrinolysis in orthopaedic operations using tourniquets in 22 patients undergoing total knee replacement. Patients were allocated to one of two groups to receive extradural anaesthesia (EA; n = 11) or general anaesthesia (GA; n = 11). The EA group received lumbar extradural block with lidocaine. The GA group received only general anaesthesia, maintained with 1.5-2.5% sevoflurane and 66% nitrous oxide in oxygen. Using a thrombelastogram technique, blood coagulability and fibrinolysis were measured. Mean maximum amplitude (MA), which reflects coagulability, increased after tourniquet inflation (11%) in group GA whereas MA in group EA did not change. After tourniquet deflation, MA values in both GA and EA groups increased significantly (10% and 20%, respectively) (P < 0.05), and there was also a significant difference in MA between groups (P < 0.05). The fibrinolytic rate did not change in either group during tourniquet inflation, but increased significantly (160%) after tourniquet deflation. There was no significant difference in fibrinolytic rate between the groups. We conclude that the hypercoagulability seen in group GA could have been caused by surgical or tourniquet pain, or both, and that extradural anaesthesia is a useful technique to prevent hypercoagulability.

Aged↗

PubMed1998

Role of intracellular Ca2+ stores in the inhibitory effect of halothane on airway smooth muscle contraction.

BACKGROUND: Halothane directly inhibits contraction of airway smooth muscle, mainly by decreasing the intracellular concentration of free Ca2+ ([Ca2+]i). The role of intracellular Ca2+ stores, sarcoplasmic reticulum, is still unclear. We investigated the role of sarcoplasmic reticulum in the inhibitory effect of halothane on contraction of airway smooth muscle by measuring [Ca2+]i and intracellular concentration of inositol 1,4,5-triphosphate ([IP3]i), a second messenger for release of Ca2+ from sarcoplasmic reticulum. METHODS: [Ca2+]i was monitored by measuring the 500-nm light emission ratio (F340/F380) of a Ca2+ indicator fura-2 with isometric tension of canine tracheal smooth muscle strip. During Ca2+-free conditions, carbachol (10(-5) M) was introduced with pretreatment of halothane (0-3%). During Ca2+-free conditions, 20 mM caffeine, a Ca2+-induced Ca2+ release channel opener, was introduced with or without halothane. We measured [IP3]i during exposure to carbachol and halothane by radioimmunoassay technique. RESULTS: Pretreatment with halothane significantly diminished carbachol-induced increases in [Ca2+]i by 77% and muscle tension by 83% in a dose-dependent manner. Simultaneous administration of halothane significantly enhanced caffeine-induced transient increases in [Ca2+]i and muscle tension in a dose-dependent manner, by 97% and 69%, respectively. Pretreatment with halothane abolished these responses. Rapid increase in [IP3]i produced by carbachol was significantly inhibited by 32% by halothane in a dose-dependent manner. CONCLUSIONS: Halothane, during Ca2+-free conditions, inhibits transient contraction of airway smooth muscle induced by muscarinic receptor stimulation, mainly by attenuating the increase in [Ca2+]i. Depletion of Ca2+ from sarcoplasmic reticulum via Ca2+-induced Ca2+ release channels also may contribute to the attenuation of the increase in [Ca2+]i by halothane.

Anesthetics, Inhalation↗

PubMed1998

[An analysis of the status of surgical transfusion in Sapporo Medical University Hospital].

To evaluate the present status of blood transfusion during operation in our hospital, we retrospectively analyzed the amount of preoperative preparation & intraoperative use of homologous blood and the circumstances of autologous blood transfusions. The amount of prepared blood was 4,505 units of which 1,187 units were transfused; the mean cross matched-to-transfused (C/T) ratio was 3.8. A trial of maximum surgical blood order schedule (MSBOS, C/T = 1.5) revealed that we could save over 70% of the homologous blood presently prepared. Preoperative blood donation (PBD) and intraoperative autologous blood transfusion (IAT) were performed in 74 cases (47.4%) and 55 cases (35.3%), respectively, of all 156 blood-transfused cases, and the operations were performed without homologous blood transfusion in 88.0% of PBD cases and 67.3% of IAT cases respectively. We are sure that the introduction of MSBOS will lead to a more efficient use of autologous blood, and that we should use homologous blood transfusion techniques so far as is possible to avoid autologous blood transfusion.

Blood Loss, Surgical↗

PubMed1998

[The effect of scalp infiltration with bupivacaine on blood coagulability and fibrinolysis in neurovascular surgery].

We investigated the effect of scalp infiltration with bupivacaine on blood coagulability and fibrinolysis in neurovascular surgery. Patients were randomly divided into two groups: scalp infiltration group (who received scalp infiltration with 0.5% bupivacaine prior to surgical incision, n = 7) and control group (n = 6). The blood coagulability and fibrinolysis were measured before and after surgical incision using a thromboelastogram (Thromboelastograph C-3000, Haemoscope). In the control group, the reaction and coagulation times were significantly shortened (30% and 23%, respectively, P < 0.05) and the maximum amplitude, which reflects coagulability, increased significantly (21%, P < 0.01) compared to each presurgical value. The scalp infiltration prior to the surgical incision prevented these reactions (P < 0.05). The fibrinolytic rate did not change in either group. We conclude that scalp infiltration prior to surgical incision is beneficial for attenuating an increase in blood coagulability, which could induce perioperative complications due to associated systemic diseases (i.e. hypertension, diabetes, ischemic heart disease, etc.).

Aged↗

PubMed1996

Direct inhibitory mechanisms of halothane on human platelet aggregation.

BACKGROUND: Although halothane directly inhibits platelet aggregation, the mechanisms of this effect are still unknown. The current study aimed to clarify the inhibitory mechanisms of halothane on thrombin-induced human platelet aggregation by measuring (1) platelet-surface glycoprotein Ib expression, (2) the concentration of intracellular free Ca2+ ([Ca2+]i) measured simultaneously with aggregation, (3) the concentration of intracellular inositol 1,4,5-triphosphate, and (4) the concentration of intracellular cyclic 3',5'-adenosine monophosphate ([cAMP]i). METHODS: Washed platelet suspensions, obtained from healthy volunteers, were preincubated with halothane (0-2 mM) for 2 min and then exposed to 0.02 units/ml thrombin for 3 min. The glycoprotein Ib bound to fluorescein-labeled antibody was measured by fluorescence flow cytometry. [Ca2+]i was measured, simultaneously with aggregation, in Fura-2 (Ca2+ indicator)-loaded platelets by use of a fluorometer. Inositol 1,4,5-triphosphate and [cAMP]i were measured by radioimmunoassay. RESULTS: Halothane had no effect on glycoprotein Ib expression with or without thrombin. Halothane decreased the thrombin stimulated [Ca2+]i transient and inhibited platelet aggregation in a dose-dependent manner, both in the presence and in the absence of external Ca2+. Isoflurane had no apparent effect on either platelet aggregation or [Ca2+]i in the absence of external Ca2+. Halothane inhibited the increase in inositol 1,4,5-triphosphate induced by thrombin. Halothane moderately but significantly increased [cAMP]i, but the adenylate cyclase activator forskolin (which has the same inhibitory ability on aggregation as halothane) increased [cAMP]i to a much greater extent than did halothane. CONCLUSIONS: Halothane inhibits thrombin-induced human platelet aggregation by decreasing [Ca2+]i without inhibiting agonist-receptor binding; the inhibitory effect of halothane on [Ca2+]i might be mediated by a decrease in inositol 1,4,5 triphosphate and in part by an increase in [cAMP]i.

Adult↗

PubMed1996

[Plasma concentration of lidocaine in patients undergoing hepatectomy with continuous epidural anesthesia--influence of extent of hepatectomy and prostaglandin E1 infusion].

We investigated changes in plasma concentration of lidocaine during continuous epidural anesthesia in 21 patients undergoing hepatectomy. According to the extent of hepatectomy, patients were assigned into one of the three groups: partial resection group, lobectomy group, and extended lobectomy group. Lidocaine 2.0 mg.kg-1 with 1: 200,000 epinephrine was epidurally administered in a bolus followed by continuous infusion of lidocaine at the rate of 1.5mg.kg-1.h-1. Plasma lidocaine concentration in the extended lobectomy group showed a significantly higher value than those of other two groups (P < 0.05). Plasma lidocaine was detected in the extended lobectomy group at 12 hs after the surgery, but not in the other two groups. Furthermore we investigated the effects of prostaglandin E1 infusion in 7 patients undergoing extended lobectomy. Plasma lidocaine concentration was not increased in this group. In conclusion, we recommend caution regarding the dose of lidocaine administered for epidural anesthesia during hepatectomy; PGE1 infusion appears to be safe in patients undergoing extended hepatectomy.

Adult↗

PubMed1996

[Anesthesia combined with profound hypothermia using cardiopulmonary bypass for clipping of giant basilar artery aneurysm].

A 52 year-old female was scheduled for clipping of giant basilar artery aneurysm. This operation needed temporary clipping of the basilar artery for 30-40 minutes, and preoperative examination suggested that some regions would become ischemic by temporary clipping. Therefore profound hypothermia using cardiopulmonary bypass (CPB) and thiamylal loading were planned to prevent cerebral damage during the operation. Anesthesia was induced with thiamylal, fentanyl, and isoflurane in nitrous oxide and oxygen. Following administration of vecuronium, trachea was intubated. Two hours after the start of surgery, thiamylal was titrated to obtain EEG patterns of burst-suppression before CPB and the infusion was continued until CPB was discontinued. With burst-suppression present, CPB was instituted. Hypothermia below 20 degrees C at pulmonary artery temperature was maintained until the aneurysm was clipped and bleeding from the operating site was controlled. Cooling and rewarming by CPB were carried out with ease and uneventfully. The patient had no neurological complications postoperatively.

Basilar Artery↗

PubMed1995

The effects of extracellular pH on intracellular pH, Ca2+ and tension of canine tracheal smooth muscle strips.

The effects of changes in extracellular pH (pHo) on intracellular Ca2+ concentration ([Ca2+]i) or intracellular pH (pHi) were measured simultaneously with muscle tension in canine tracheal smooth muscle strips. [Ca2+]i and pHi were measured using the fluorescent dyes fura-2 and BCECF, respectively. During high K(+)-induced contractions (24.2, 36.4 or 72.7 mM) at pH 7.4, pHo was changed to 7.8 or 7.0 with NaOH or HCl, respectively. Induced changes in pHi were equal to approximately 50% of the changes in pHo. Alkalinization significantly increased [Ca2+]i and enhanced muscle contraction at all concentrations of K+ but did not alter the relationship between muscle tension and [Ca2+]i. Acidification significantly decreased [Ca2+]i without changing muscle tone; hence, the muscle tension-[Ca2+]i relationship was shifted to the left. These results suggest that changes in pHo can alter airway smooth muscle tone by changing [Ca2+]i and pHi.

Animals↗

PubMed1995

[Fatigue and stress of anesthesiologists at work--third report: investigation with a flicker photometer and a stabilo-meter].

We previously studied the fatigue and stress of anesthesiologists at work using a flicker photometer, visual reaction time test, questionnaires, and Holter EKG. In the present study, we investigated the fatigue and stress in seven junior anesthesiologists at work using a flicker photometer and a stabilo-meter. The stabilo-meter measures postural stabilization. We performed each test three times on each subject for a total of twenty-one times. The flicker test and the stabilo-test showed the increase in fatigue in 17 (18%) and in 16 tests (76%), respectively, in all seven subjects. Increase of fatigue in both the flicker and stabilo-tests was observed in 13 tests (61%) of 6 subjects. There was a good relationship between the flicker test and the stabilo-test. Therefore, the stabilo-test appears to be a useful method for investigating the fatigue of anesthesiologists.

Anesthesiology↗

PubMed1994

Inhibitory effects of halothane on high(K+)-induced canine tracheal smooth muscle contraction and intracellular Ca2+ increment.

Halothane is a potent bronchodilator. The effects of halothane on isolated canine tracheal smooth muscle contraction and intracellular Ca(2+) increment induced by a high concentration of K+ were investigated to clarify how this anaesthetic decreases intracellular Ca2+ concentration ([Ca2+]i), an important second messenger. The tension of the muscle strips was measured using an isometric transducer, and [Ca2+]i was measured using a surface fluorescence spectroscopy. Exposure to a 72.7 mM K+ solution increased muscle tension and [Ca2+]i. Halothane (1,2,3 and 4% at the vaporiser) was introduced by bubbling in the presence of the 72.7 mM K+, and significantly decreased both this elevated muscle tension and the [Ca2+]i in a concentration-dependent manner. Similarly, slowly decreasing concentrations of K+ (48.5, 36.4, 24.2 and 18.2 mM) significantly decreased both of these variables. There was no significant difference between the slopes of the two regression lines of changes in muscle tension and changes in [Ca2+]i. From the evidence that tonic increase in [Ca2+]i by high concentrations of K+ is due to the influx of Ca2+ via L-type voltage channels, halothane may modify the L-type channels to decrease Ca2+ influx. In conclusion, halothane inhibits the high K(+)-induced canine airway smooth muscle contraction by decreasing [Ca2+]i. The decrease in [Ca2+]i by halothane might be due to inhibition of voltage-operated channels, especially the L-type channels.

Animals↗

PubMed1993

Inhibitory effects of four inhaled anesthetics on canine tracheal smooth muscle contraction and intracellular Ca2+ concentration.

To clarify the mechanisms by which inhaled anesthetics directly inhibit tracheal smooth muscle contraction, we investigated the effects of these anesthetics on muscle tension and intracellular Ca2+ concentration ([Ca2+]i). Tension was measured using an isometric transducer, and [Ca2+]i was measured using Fura-2, an indicator of [Ca2+]i. Addition of 1 microM carbachol increased muscle tension and [Ca2+]i. All inhaled anesthetics significantly decreased both muscle tension and [Ca2+]i in the following order of inhibitory potency: halothane >> isoflurane > enflurane >> sevoflurane. In the presence of 10 microM verapamil, carbachol moderately increased muscle tension, but induced a transient increase of [Ca2+]i followed by a substantial reduction. Inhaled anesthetics in the presence of both carbachol and verapamil significantly decreased muscle tension without decreasing [Ca2+]i. Potency for suppression of tension under these conditions, which appeared to be independent of [Ca2+]i, was in the order: halothane >> enflurane > or = isoflurane >> sevoflurane. The best correlation we found with a measured reduction of muscle tension independent of [Ca2+]i was with oil/gas partition coefficients (r = -0.88, P < 0.001). In conclusion, inhaled anesthetics inhibit tracheal smooth muscle contraction by at least two mechanisms: 1) reduction of [Ca2+]i and 2) suppression of contractility, independent of [Ca2+]i. The close correlation between the muscle inhibition independent of [Ca2+]i and the oil/gas partition coefficients suggests that one of the major sites of action of inhaled anesthetics is membrane phospholipids.

Anesthetics↗

PubMed1992

[Two cases of diffuse pulmonary lymphangiomyomatosis].

We cared 2 patients with diffuse pulmonary lymphangiomyomatosis (LAM) through the perioperative period. LAM is a disease of uncertain origin and poor prognosis because of respiratory failure. Therefore, it is important to provide not only a good anesthetic care but also a good preoperative respiratory care. In the first case (a 35-yr-old woman), an open lung biopsy was performed after dyspnea and sputum had disappeared with preoperative medications of a bronchodilator and some antibiotics. In the second case (a 35-yr-old woman), oophorectomy was performed after FEV1.0% had remarkably increased with preoperative medication of a bronchodilator. Both patients did well through the perioperative period without any trouble or complications, such as pneumonia or severe hypoxemia, presumably owing to our perioperative management system.

Adult↗