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Biomedical subjects

K Omote

Publications and source records attributed to K Omote.

At least 55 records · Page 3Linked to original sources
PubMed1996

[Analgesic mechanism of ketamine].

The present study was conducted to investigate the mechanism of antinociceptive action of ketamine in rats. Intraperitoneally administered ketamine showed antinociception in the tail flick (TF) and mechanical paw pressure (MPP) tests in a time- and dose-dependent manner. However, intrathecal ketamine, 50-1,000 micrograms, did not exert any antinociceptive effect in TF and MPP tests. In contrast to the antinociceptive actions of intraperitoneal ketamine in TF test in intact rats, ketamine did not produce any effect in spinally transected rats. Further, pretreatment with an intrathecal serotonin antagonist, methysergide, and an intrathecal alpha 2 adrenergic antagonist, yohimbine, abolished the antinociceptive effects of intraperitoneal ketamine in the TF and the MPP tests. The monoamine levels (noradrenaline, MHPG, 5-HT, 5-HIAA) in the spinal cord, which were measured by high performance liquid chromatography, increased after the intraperitoneal administration of ketamine. We conclude that the antinociceptive effects of ketamine involve an activation of the monoaminergic (noradrenergic and serotonergic) descending inhibitory system, and that spinal ketamine does not affect the responses to the acute noxious stimuli.

Analgesics↗
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

[Potentiation of procaine-induced local sensory block by verapamil in rats].

We have studied the effects of calcium-channel blocker, verapamil, on procaine-induced local sensory block. Standardized tail-flick (TF) test was used to investigate the duration and intensity of procaine-induced local conduction block in rats. After obtaining baseline TF latencies (mean; 3.3 sec), two 100 microliters of 0.4% procaine alone, a combination of 0.4% procaine and verapamil (100 micrograms, or 200 micrograms), or a large dose of verapamil (200 micrograms) were injected to the opposite sites of the tail base and TF test was performed every five minutes for 45 minutes. A large dose of verapamil showed no prolongation of TF latencies. The administration of 0.4% procaine alone produced a significant increase of TF latencies and the peak effect of % MPE (percent maximum possible effect) was demonstrated at 4 minutes after the drug injection (mean % MPE; 37.0%). Coadministration of 0.4% procaine and two doses of verapamil produced significant increases of % MPE in a dose-dependent fashion. It was concluded that sensory block by procaine of the peripheral nerves is potentiated by coadministration of calcium-channel blocker, verapamil.

Anesthetics, Local↗
PubMed1996

[Local anesthetics].

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Adrenergic alpha-Agonists↗
PubMed1995

Acute pulmonary edema associated with transfusion of packed red blood cells.

We experienced a patient who suffered noncardiogenic acute pulmonary edema after transfusion of packed red blood cells which contained antigranulocyte antibodies. The data suggested that complement activation and the release of polymorphonuclear protease were involved in the pathogenesis of the complication in the present patient. Furthermore, blood coagulative system was also activated after the transfusion. The underlying mechanisms of the complication are discussed.

Acute Disease↗
PubMed1995

Effects of verapamil on spinal anesthesia with local anesthetics.

The primary mode of action of local anesthetics is through sodium channel and axonal conduction blockade. Local anesthetics also have extensive effects on presynaptic calcium channels that must function to stimulate the release of neurotransmitters. Thus, interference with calcium channel conductance may enhance spinal anesthesia with local anesthetics. The present study was designed to investigate the effects of the intrathecal calcium channel blocker, verapamil, on the spinal anesthesia from lidocaine and tetracaine. Male Sprague-Dawley rats were chronically implanted with lumbar intrathecal catheters. Tail-flick (TF) and mechanical paw pressure (MPP) tests were used to assess thermal and mechanical nociceptive threshold, respectively. Motor function was assessed using a modified Langerman's scale. Intrathecal lidocaine or tetracaine alone showed the prolongation of TF latency, the increase of MPP threshold, and the increase in motor function scale in a time- and dose-dependent manner. Although intrathecal verapamil alone demonstrated neither sensory nor motor block at the doses used (50-200 micrograms), the combination of lidocaine (20, 50, 100, or 200 micrograms) or tetracaine (10, 20, 50, or 100 micrograms) and verapamil (50 micrograms) produced the more potent and prolonged antinociception and motor block when compared with local anesthetics alone. We interpreted these results to indicate that the intrathecal calcium channel blocker, verapamil, potentiates spinal anesthesia with local anesthetics.

Anesthesia, Spinal↗
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↗
PubMed1995

[Interaction between opiate subtypes and serotonin in suppressing noxiously evoked activity of WDR neurons].

The present study examined interactions between mu and delta opiate subtypes and serotonin. Noxious activity evoked by radiant heat (51 degrees C, 8 sec) was extracellularly recorded from single discriminated wide dynamic range (WDR) neurons in decerebrate spinally transected cats. DAGO (mu selective opioid agonist) 1 microgram or DPDPE (delta selective opioid agonist) 30 micrograms was combined with serotonin (n = 6 each) 250 micrograms. The dose of each drug by itself when administered intrathecally produced no suppression of noxiously evoked activity. Although the combination of DAGO and serotonin produced no significant suppression of noxiously evoked activity, DPDPE and serotonin produced significant suppression to 72.8 +/- 8.0 % (mean +/- SEM) of control values (P < 0.01). Intravenously administered naloxone 0.1 mg reversed the suppression produced by the DPDPE-serotonin combination. Our results suggest that combinations of serotonin and delta selective opiates may be more effective in suppressing noxiously evoked activity than combinations with mu selective opiates.

Animals↗
PubMed1995

[Effects of oral alpha 2 adrenergic agonists, clonidine and tizanidine, on tetracaine spinal anesthesia].

This study was conducted to evaluate the effects of oral clonidine and tizanidine, alpha 2 adrenergic agonists, as premedication for tetracaine spinal anesthesia in 63 gynecological patients. The patients were randomly allocated to one of six groups. Group 1 (n = 7), group 2 (n = 8) and group 3 (n = 7) received 13 mg of tetracaine intrathecally in 10 % glucose solution 2.6 ml. Group 4 (n = 13), group 5 (n = 14) and group 6 (n = 13) received 13 mg of tetracaine intrathecally in a volume of 2.6 ml of 10 % glucose solution which contained 0.65 mg of phenylephrine. As premedication, group 1 and 4 received 0.25 mg of oral triazolam; group 2 and 5 received 3 mg of oral tizanidine; group 3 and 6 received 0.15 mg of oral clonidine. Group 2 and 3, or group 5 and 6 (clonidine or tizanidine group, respectively) needed significant longer time for regression of Th10 sensory blockade than group 1 or 4 (triazolam). The time for appearance of postoperative pain and the time to require postoperative analgesics were longer in the groups which had received either clonidine or tizanidine than in the groups which had received triazolam. Heart rate and systolic blood pressure in group 6 (clonidine-tetracaine-phenylephrine group) showed significant decreases (P < 0.05) after the spinal anesthesia. We concluded that oral premedication of clonidine and tizanidine prolonged tetracaine spinal anesthesia. From the view point of the prolongation of spinal anesthesia and the hemodynamic stability, oral premedication with tizanidine seems to be useful.

Administration, Oral↗
PubMed1994

Differential neuromuscular effects of vecuronium on the adductor and abductor laryngeal muscles and tibialis anterior muscle in dogs.

We have studied in dogs the neuromuscular blocking effects of vecuronium on the cricothyroid (CT) (a tensor muscle of the vocal folds) and posterior cricoarytenoid (PCA) (sole abductor muscle of the vocal folds) muscles of the larynx and the tibialis anterior (TA) muscle. The lungs of the animals were ventilated mechanically with 0.2% halothane and oxygen. Electromyography (EMG) was performed on the CT, PCA and TA muscles by inserting fine wire electrodes. The evoked compound EMG responses of the three muscles were measured simultaneously in an identical manner by stimulating supramaximally the superior laryngeal, recurrent and sciatic nerves at 0.1 Hz and 0.2 ms. Vecuronium was infused continuously at a rate of 0.01 mg kg-1 min-1 for 8 min. Vecuronium produced more intense neuromuscular block in the CT than in the PCA and TA muscles. The rate of recovery was significantly slowly in the CT compared with the PCA and TA muscles. This study confirms the difference in sensitivity between laryngeal and peripheral muscles, demonstrating that the intrinsic laryngeal muscles do not all behave similarly after administration of vecuronium.

Action Potentials↗
PubMed1994

Sympathetic ganglion blockade for the management of hyperhidrosis.

We present three patients with severe primary hyperhidrosis, refractory to conservative medical treatment, who were successfully managed with sympathetic ganglion blockade with ethanol. We also summarize 10 patients with hyperhidrosis who underwent sympathetic ganglion blockade in the past 2 years. This closed percutaneous method offers the patients considerably less discomfort and less stress with minimal morbidity and has a efficacy similar to that of surgical sympathectomy, which has previously been the only effective and permanent therapy for severe primary hyperhidrosis. It is concluded that chemical sympathectomy is an effective and useful method for treating severe hyperhidrosis which has advantages over surgical sympathectomy.

Adult↗
PubMed1994

Measurement of intercostal and pleural pressures by epidural catheter.

The pressures in the intercostal and interpleural spaces were measured in 20 patients using an 18 gauge epidural catheter to confirm accurate catheter positioning for continuous intercostal and interpleural local anaesthetic blockade. In the intercostal space the mean (SD) pressure was negative (-1.8 (0.3)) mmHg and positive (+2.1 (0.3)) mmHg at the end of inspiration and expiration respectively. In contrast, in the interpleural space although the pressure varied with the respiratory cycle it remained negative both at the end of inspiration (-8.3 (1.0)) mmHg and expiration (-2.1 (0.8)) mmHg. We conclude that measurement of intercostal and interpleural pressures with an epidural catheter is a straightforward procedure which may be helpful in confirming accurate catheter placement for continuous intercostal or interpleural local anaesthetic blockade.

Adult↗
PubMed1994

Effects of morphine on neuronal and behavioural responses to visceral and somatic nociception at the level of spinal cord.

This study was undertaken to examine the role of morphine in modulation of nociception in visceral and somatic pain tests at the level of the spinal cord, using neurophysiological and behavioural reflex assays. In the neurophysiological study, we recorded extracellularly the activity of the single viscero-somatic convergent neurons of the spinal dorsal horn, which was evoked by the colorectal distention (80 mmHg) of noxious visceral stimulation and the radiant heat (51 degrees C) of noxious somatic stimulation, in decerebrated, spinally transected cats. Spinally administered morphine (200 micrograms) produced significant suppression of noxiously evoked activity by both stimuli in a time-dependent manner. In addition, intravenously administered naloxone reversed the suppressive effects of morphine. In the behavioral reflex study, colorectal distension threshold and tail-flick latency were measured in rats chronically implanted with lumbar intrathecal catheter. Intrathecally administered morphine significantly elevated the colorectal distension threshold and prolonged the tail-flick latency in a time- and dose-dependent manner. The results of the present study demonstrated that spinal morphine was capable of suppressing the evoked activity of the viscero-somatic convergent neurons, resulting in suppression visceral and somatic pain behavioral reflexes.

Afferent Pathways↗
PubMed1994

Acetic acid intoxication by rectal administration.

The enhanced toxicity of acid instilled directly into the rectum, without benefit of dilution and neutralization in the upper intestine, is evident in a case of acetic acid intoxication by accidental rectal administration of 50 mL of 9% acetic acid to a 5-year-old boy. The complications included necrosis of the colon, acute renal failure, acute liver dysfunction, disseminated intravascular coagulopathy (DIC) and sepsis.

Acetates↗
PubMed1994

[Evaluation of analgesic effects of morphine, buprenorphine and pentazocine in rats receiving somatic and visceral stimulation].

The analgesic effects of morphine, buprenorphine and pentazocine examined by behavioral responses to tail-flick (TF) and colorectal distension (CD) were studied in rats. Animals were randomly divided into three groups; morphine (M) groups of 4 mg.kg-1 (n = 7), buprenorphine (B) groups of 0.03 mg.kg-1 (n = 8), pentazocine (P) groups of 3 mg.kg-1 (n = 8). After determinations of TF and CD values, animals were administered each analgesic intraperitoneally, and both procedures were repeated every 5 minutes until 40 minutes. Three drugs produced an almost same degree of increase in pain threshold for TF; % maximum possible effects (%MPEs) were approximately 30%. Similar patterns of increase in pain thresholds for CD were observed in M and B groups; %MPEs were approximately 20%. In contrast, P groups showed a significant increase in thresholds for CD compared to M and B groups; 20 minutes after intraperitoneal administration of P, %MPE was approximately 50%. These results indicate that there are different antinociceptive effects to somatic and visceral stimuli between M, B and P, and suggest that selective opioid agonists modulate responses to different kinds of noxious stimuli.

Abdominal Pain↗