Biomedical subjects

M Miyabe

Publications and source records attributed to M Miyabe.

At least 55 records · Page 3Linked to original sources

PubMed1994

Inhibitory effect of topical application of polymerized ferulic acid, a synthetic lignin, on tumor promotion in mouse skin two-stage tumorigenesis.

A dehydrogenation polymer of ferulic acid (DHP-FA), a synthetic lignin, was evaluated for its ability to inhibit tumor promotion by 12-O-tetradecanoylphorbol-13-acetate (TPA) in the 7,12-dimethylbenz[a]anthracene-treated skin of female ICR mice. Topical application of DHP-FA inhibits TPA-induced tumor promotion, whereas a monomeric ferulic acid does not show the inhibitory effect.

9,10-Dimethyl-1,2-benzanthracene↗

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

Competitive N-methyl-D-aspartate receptor blockade reduces brain injury following transient focal ischemia in cats.

BACKGROUND AND PURPOSE: We tested the hypothesis that administration of the competitive N-methyl-D-aspartate (NMDA) receptor antagonist NPC 17742 (2R,4R,5S-[2-amino-4,5-(1,2-cyclohexyl)-7-phosphonoheptanoic acid]) during transient focal ischemia affects early postischemic brain injury. METHODS: Halothane-anesthetized cats underwent 1 hour of left middle cerebral artery occlusion plus 4 hours of reperfusion. Control cats received saline (n = 7). Experimental cats were treated with NPC 17742 at a dose of 5 mg/kg IV from 45 minutes of ischemia to 15 minutes of reperfusion and 2.5 mg/kg per hour for 4 hours of reperfusion (NPC-5; n = 7) or 50 mg/kg from 45 minutes of ischemia to 15 minutes of reperfusion and 25 mg/kg per hour for 4 hours of reperfusion (NPC-50; n = 5). RESULTS: Microsphere-determined blood flow to the ipsilateral inferior temporal cortex and caudate nucleus decreased to the same extent during ischemia and recovered to the same extent during reperfusion in the three groups. Triphenyltetrazolium-determined injury volume of ipsilateral cerebral hemisphere (saline, 24 +/- 8%; NPC-5, 4 +/- 2%; NPC-50, 5 +/- 2% of hemisphere; mean +/- SE) and caudate nucleus (saline, 72 +/- 6%; NPC-5, 37 +/- 10%; NPC-50, 26 +/- 4%) was less in cats treated with both doses of drug compared with cats treated with saline. Recovery of somatosensory evoked potential amplitude was incomplete and similar in all groups (saline, 36 +/- 14%; NPC-5, 58 +/- 8%; NPC-50, 51 +/- 15% of baseline). CONCLUSIONS: These data indicate that activation of NMDA receptors plays an important role in the mechanism of acute injury in both cortex and caudate after 1 hour of transient focal ischemia in the cat. Because NPC 17742 afforded protection when administered at the end of ischemia and during reperfusion, NMDA receptor activation during reperfusion may contribute to the progression of injury in ischemic border regions.

Amino Acids↗

PubMed1994

Nitric oxide synthase inhibition reduces caudate injury following transient focal ischemia in cats.

BACKGROUND AND PURPOSE: We tested the hypothesis that inhibiting nitric oxide production either before or during transient focal ischemia affects early postischemic brain injury. METHODS: Halothane-anesthetized cats underwent 1 hour of left middle cerebral artery occlusion plus 3 hours of reperfusion. Pretreatment groups received either intravenous N omega-nitro-L-arginine methyl ester (L-NAME; 10 mg/kg, n = 10) or an equal volume of diluent (10 mL saline, n = 10) over 30 minutes before ischemia. Posttreatment groups received intravenous L-NAME (10 mg/kg) over 30 minutes from 45 minutes of ischemia to 15 minutes of reperfusion (n = 10) or intravenous L-NAME (10 mg/kg) plus L-arginine (200 mg/kg) over the same period followed by continuous L-arginine infusion (200 mg/kg per hour) for the remainder of reperfusion (n = 10). RESULTS: Microsphere-determined blood flow to ipsilateral caudate nucleus and inferior temporal cortex decreased to the same extent during ischemia and recovered to the same extent during reperfusion in the four groups. Triphenyltetrazolium-determined injury volume of ipsilateral caudate nucleus in cats treated with L-NAME before or during ischemia (42 +/- 7% and 42 +/- 3% of caudate nucleus, respectively; mean +/- SE) was less (P < .05) compared with that in cats pretreated with saline (72 +/- 5%) or cats treated with L-NAME plus L-arginine (68 +/- 5%). Ipsilateral cerebral hemispheric injury volume was similar among the four groups (23 +/- 5%, 13 +/- 3%, 18 +/- 5%, and 29 +/- 5% of hemisphere in groups treated with L-NAME before ischemia and during ischemia, the saline-treated group, and the group treated with L-NAME plus L-arginine, respectively). CONCLUSIONS: Inhibition of nitric oxide synthase decreases caudate injury volume from transient focal cerebral ischemia in cats. The beneficial effect is reversed by L-arginine and is not caused by favorable redistribution of blood flow during ischemia and reperfusion. Because L-NAME was efficacious when administered at reperfusion, nitric oxide generated during reperfusion appears to contribute to caudate injury.

Amino Acid Oxidoreductases↗

PubMed1994

[Study of administration of buprenorphine suppository for postoperative pain relief following transvaginal hysterectomy].

Buprenorphine suppository (BSP) has been available as an analgesic agent in Japan since 1990. It has gained considerable popularity in various clinical situations; however, its usefulness for postoperative pain relief has been controversial. The present study is addressed to postoperative pain in fifty-seven women who underwent transvaginal hysterectomy under spinal anesthesia with tetracaine and phenylephrine. We examined the analgesic effects of buprenorphine (0.4 mg) suppository. Patients were divided into four groups according to the timing of buprenorphine suppository administration: group A1, preoperative administration of BSP, n = 12; group A2, postoperative administration of BSP, n = 17; group A3, intravenous injection of 0.1 mg of buprenorphine during surgery and postoperative administration of BSP, n = 14; group C, control group, n = 14. All the patients in group C complained of pain within 24 hr. The onset time of pain after surgery was significantly longer in patients in group A1 (372 +/- 220 min) and A3 (481 +/- 161 min) than in control group C (282 +/- 97 min). The percentage of patients who did not complain of pain within 24 hr was the largest in group A3 (36%). However there were no significant differences in age, body weight, effective analgesic time, analgesic level or operation time among the four groups. Nausea and vomiting were observed in all groups: C (36%), A1 (41%), A2 (18%), and A3 (29%). From these results, we conclude that preoperative or intraoperative administration of buprenorphine is useful for control of postoperative pain; the method of administration of buprenorphine suppository needs further study.

Adult↗

PubMed1994

[Open heart surgery in patient with hyperthyroidism].

A 57-yr-old male with atrial septal defect (ASD) was scheduled for the patch closure operation. The patient had a history of hyperthyroidism due to giant adenoma of the thyroid gland. The patient was controlled under euthyroid state by thiamazole for four years. With this treatment, his thyroid function became normal and he was doing well for over the last seven years. On the morning of the day of operation, thiamazole was given orally to this patient. When the ASD patch closure was performed, the examination of his thyroid gland revealed hypothyroidism, but the operation could be performed without any thyroidal trouble. After the operation thiamazole was given intramuscularly to this patient and from the next day it was continued orally. Thyroid storm did not occur after the operation until discharge. We conclude that in a case of heart disease with hyperthyroidism, it is important to keep the patient's thyroid function under normal for a long time before surgery.

Administration, Oral↗

PubMed1993

The effect of head-down tilt on arterial blood pressure after spinal anesthesia.

We examined the usefulness of 10 degrees head-down tilt for hypotension after spinal block. Two different investigations were performed, one employing head-down tilt after arterial blood pressure had decreased (n = 40), and the other using a prophylactic tilt (n = 50). When the head-down tilt was applied to treat hypotension after spinal block (n = 40), arterial blood pressure increased only in patients whose systemic blood pressure decreased more than 30% from the control (severe hypotension group, n = 11). However, even in the severe hypotension group, systolic blood pressure did not increase in two patients after 10 degrees head-down tilt. When the head-down tilt was performed immediately after spinal block (n = 24), the changes in systolic blood pressure were the same as in the horizontal group (n = 26). The cephalad spread of analgesia at 20 min after spinal block was higher, however, in the head-down tilt group (T3.8 +/- 1.6) than the horizontal group (T5.2 +/- 1.9). From these results we conclude that head-down tilt for hypotension after spinal block increases arterial blood pressure only for severe hypotension, and that prophylactic head-down tilt has no effect in maintaining blood pressure.

Adult↗

PubMed1993

[Evaluation of low flow closed anesthesia technique for oxygen, nitrous oxide and isoflurane using Engström Elsa Anesthesia System].

We studied low flow closed anesthesia technique for oxygen, nitrous oxide and isoflurane using Engström Elsa Anesthesia System in 47 patients undergoing elective surgery. In the low flow group, anesthesia was maintained with oxygen 300 ml.min-1, nitrous oxide 300 ml.min-1 and optimal concentration of isoflurane after endotracheal intubation. The inspired oxygen concentration was kept higher than 35% through the operation. In the minimal flow group, anesthesia was maintained with nitrous oxide 4 l.min-1, oxygen 2 l.min-1 and optimal concentration of isoflurane after intubation until the inspired oxygen concentration reached approximately 35%. Then the fresh gas flow was reduced to oxygen 250 ml.min-1 and nitrous oxide 250 ml.min-1. In order to maintain the inspired oxygen concentration at 35%, the flow of nitrous oxide should have been reduced as low as to 150 ml.min-1 after 240 min. The volumes of consumption of nitrous oxide and isoflurane in the low flow and minimal flow groups were reduced to one fifth and one third respectively, compared with those of the high flow group. In conclusion, we can perform low flow closed anesthesia safely and easily with this equipment.

Adult↗

PubMed1993

[Continuous thoracic epidural blockade in combination with general anesthesia with nitrous oxide, oxygen, and sevoflurane in two patients with myasthenia gravis].

Continuous thoracic epidural anesthesia (T4/5) using 4-5 ml.h-1 of 1.5% lidocaine with 1:200,000 epinephrine and inhaled anesthesia using nitrous oxide, oxygen and sevoflurane were performed in two patients, (40 and 22 yr-old females) with myasthenia gravis. This combined anesthetic technique provided muscle relaxation for endotracheal intubation and optimal operating conditions, including muscle relaxation and stability of hemodynamics during transsternal thymectomy. Further, continuous epidural anesthesia using 4 ml.h-1 of 0.25% bupivacaine provided postoperative pain relief without other analgesics and stable postoperative respiratory conditions. In conclusion, we confirm the benefits of this technique which provides not only safe and stable conditions during the surgery, but also an improved comfort for patients in the postoperative period following transsternal thymectomy for myasthenia gravis.

Adult↗

PubMed1992

[Intrathecal morphine for postoperative pain relief after transvaginal hysterectomy].

We studied the effect of a low-dose intrathecal morphine (0.1 or 0.2 mg) in postoperative pain relief and the incidence of side effects. Two hundred and fifteen patients scheduled for transvaginal hysterectomy were divided into 3 groups according to intrathecal morphine doses: M1 (morphine 0.1 mg N = 75), M2 (morphine 0.2 mg N = 69) and C (control N = 71). A standard mid-line lumbar puncture was performed using a 25-gauze needle in the L3/4 interspace. Preservative-free morphine hydrochloride mixed in hyperbaric tetracaine solution was administered intrathecally. Pain relief was significantly greater for the first 24 hrs in groups M1 and M2 compared with group C. Respiratory depression was not seen in any groups. The incidence of vomiting was about 40% in all groups. We conclude that intrathecal morphine 0.1-0.2 mg is useful for pain relief after transvaginal hysterectomy and accompanies no major side effects.

Adult↗

PubMed1992

[Deep neck infection following endotracheal intubation].

A 71-year-old woman was transferred to Kushiro City General Hospital because of fever, sore throat, diffuse neck swelling and dyspnea. She had received right mastectomy for breast cancer under general anesthesia 6 days before the admission. The lateral X-ray film of the neck revealed abscess in the retropharyngeal space and the retroesophageal space. CT scan revealed mediastinitis. Next day she received neck dissection for drainage of the abscess under general anesthesia. Although the posterior pharyngeal wall was swollen, endo-tracheal intubation was not difficult. Brown tinged and purplish pus was aspirated from the interspace of carotid sheath and trachea, the retropharyngeal space, and the superior mediastinal space. The infected site was irrigated with a lot of peroxide and saline and draining tubes were placed in each interspace. Tracheostomy was not done but the patient was admitted to the ICU with her trachea intubated. The day after operation, she was extubated. Three days after the operation chest X-ray revealed pyothorax and chest tube was inserted for drainage. Seven days after the operation she was transferred to the ENT ward. Thereafter her recovery course was uneventful. It seems that the deep neck infection was probably caused by the injury on endotracheal intubation at the first operation in this case. Although this patient was cured of mediastinitis following deep neck infection, which is still lethal, early diagnosis and surgical drainage of the abscess are necessary.

Abscess↗

PubMed1992

[An unusual cause of anesthetic ventilator malfunction].

We report a case of malfunction of an anesthetic ventilator by an unusual cause. A 48-year-old male with gastric cancer was scheduled for gastrectomy. Anesthesia was maintained with enflurane, N2O, O2 and epidural blockade using a semiclosed circuit system. The patient was ventilated using AV1 anesthetic machine (Dräger Co.). Forty minutes after induction of anesthesia, chest movement of the patient suddenly stopped. There was no gas flow to the patient during inspiratory phase. Air leak was not found in anesthetic respiratory circuit and at the bellows of the ventilator. The supply of oxygen and air to the anesthetic machine was sufficient. Since we could not find any cause of the ventilator failure, anesthesia was maintained with manual ventilation by using another anesthetic machine until completion of the surgery. After the surgery, we recognized that the controller unit of expiratory valve of the ventilator was obstructed by a Tamper Proof Film, which seals the outlet of a commercial bag of lactated Ringer's solution (Solulact, Terumo Co.). It seems that the film dropped accidentally between the main part and the ventilator system of anesthetic machine when the bellows was exchanged before the surgery, and moved on to the controller unit of the expiratory valve of the ventilatory system during surgery. In conclusion, it is necessary for anesthetists to understand the inner structure and system of the anesthetic machine and to check the anesthetic machine to avoid the troubles and accidents related to anesthetic machine.

Anesthesia, Closed-Circuit↗

PubMed1992

[Hemodilutional and blood salvaging autotransfusions in a case of aplastic anemia].

A 28-year-old female, weighing 46 kg, 155 cm in height, with aplastic anemia underwent implantation of iliac bone to the head of the femur. A combined technique of hemodilution and intraoperative blood salvaging was applied to supplement the blood loss during the operation. Intraoperative monitoring included continuous arterial pressure, heart rate, electrocardiograph, SVO2, bleeding time, prothrombin time (PT), activated thromboplastin time (APTT), and thromboelastography. A total of 900 ml of blood was drawn and the same volume of 5% albumin solution was infused over half an hour before the beginning of the surgery. During the operation, 2100 ml of blood was lost, and 1260 ml of autologous blood, 400 ml of homogeneous red blood cells and 5 units of fresh platelet were infused. The values of PT, APTT, bleeding time were within normal ranges after the surgery. Only 3 units of fresh platelet was infused in 2 weeks after the surgery. It was suggested that hemodilution and salvaging autotransfusion is safely performed and beneficial to minimize homogeneous blood transfusion even in a case of aplastic anemia.

Adult↗

PubMed1991

[Continuous infusion of ketamine and midazolam for prolonged sedation in the intensive care unit].

The clinical effects and pharmacokinetics of ketamine and midazolam, administered continuously for prolonged sedation were studied in 7 critically ill patients under mechanical ventilation. Initially ketamine 1 mg.kg-1 and midazolam 0.1 mg.kg-1 were administered intravenously and these were followed by infusion at a rate of 1.0 mg.kg-1.hr-1 of ketamine and 0.05 mg.kg-1.hr-1 of midazolam. The infusion rate was changed every 30 minute with increments of 0.5 mg.kg-1.hr-1 of ketamine and 0.05 mg.kg-1.hr-1 of midazolam until the sedative score by Ramsy RAE reached rank 4 (i.e. slow response to loud verbal commands). The plasma concentrations of ketamine were analyzed using high performance liquid chromatography and those of midazolam using gas chromatography. The mean maintenance doses of ketamine and midazolam were 2.25 +/- 0.61 mg.kg-1.hr-1 and 0.11 +/- 0.05 mg.kg-1.hr-1 (mean +/- SD), respectively. There were no significant changes in blood pressure or heart rate before and after the injection of ketamine and midazolam in all the patients. The plasma concentrations of ketamine and midazolam were 2.98 +/- 0.20 micrograms.ml-1 and 494.1 +/- 66.7 ng.ml-1, respectively. The time to clear response to verbal commands after cessation of the continuous infusion was 168 +/- 109 min. The plasma concentrations of ketamine and midazolam decreased rapidly, and plasma half-life of ketamine was about 1 hour and for midazolam less than 2 hours. In conclusion, continuous infusion of ketamine and midazolam was very useful to sedate critically ill patients under mechanical ventilation, with minimal effect on the cardiovascular system and rapid recovery of consciousness.

Adult↗

PubMed1991

[Sevoflurane with continuous epidural anesthesia for removal of pheochromocytoma].

A 66-year-old female was scheduled for right adrenalectomy because of a pheochromocytoma. Preoperative blood pressure was well controlled with an alpha.beta blocker, amosulalol hydrochloride 40 mg per day po for 2 weeks. The patient received midazolam 2.5 mg im and scopolamine 0.4 mg im 60 minutes before induction. Anesthesia was induced with midazolam 5 mg iv, fentanyl 0.1 mg iv and vecuronium 12 mg iv, and maintained with continuous epidural infusion of 1.5% lidocaine, and inhalation of 66% nitrous oxide in oxygen and sevoflurane (0.5-3%). Blood pressure was controlled with nicardipine (1-6 micrograms.kg-1.min-1) before removal of the pheochromocytoma. After removal of the tumor blood pressure was maintained with intravenous infusion of lactated Ringer's solution, dopamine (3-8 micrograms.kg-1.min-1), dobutamine (3-8 micrograms.kg-1.min-1) and norepinephrine (0.1-0.2 micrograms.kg-1.min-1). A combination of continuous epidural block and sevoflurane anesthesia was very useful for removal of the pheochromocytoma. Swan-Ganz catheter monitoring was also very useful before and during operation to determine the optimal doses of nicardipine, catecholamine and the volume of transfusion.

Adrenal Gland Neoplasms↗

PubMed1989

Chemodenervation does not alter cerebrovascular response to hypoxic hypoxia.

We tested the hypothesis that sinoaortic chemodenervation would alter the increase in cerebral blood flow (CBF) during isocapnic hypoxic hypoxia in 1- to 7-day-old lambs. Lambs were anesthetized with pentobarbital and studied during moderate (arterial O2 content [CaO2] = 10 vol/100 ml) and severe (CaO2 = 6 vol/100 ml) hypoxic hypoxia. Regional brain blood flows were measured with the radioactive microsphere technique. Cerebral oxygen consumption (CMRO2) was calculated as the product of forebrain blood flow and the difference in oxygen contents between arterial and sagittal sinus blood. Lambs were then subjected to either sham surgery (n = 6) or to carotid chemodenervation and cervical vagotomy (n = 6). Chemodenervation was verified by abolition of the transient increase in blood pressure after intravenous injection of sodium cyanide in intact subjects. Neither sham surgery nor chemodenervation had an effect on CMRO2 or CBF during hypoxic hypoxia. These data thus do not support the hypothesis that arterial chemoreceptors play any substantial role in the regulation of cerebral vascular tone during hypoxic hypoxia in the 1- to 7-day-old anesthetized lamb.

Animals↗

PubMed1989

Hypercapnia and response of cerebral blood flow to hypoxia in newborn lambs.

Individual effects of hypoxic hypoxia and hypercapnia on the cerebral circulation are well described, but data on their combined effects are conflicting. We measured the effect of hypoxic hypoxia on cerebral blood flow (CBF) and cerebral O2 consumption during normocapnia (arterial PCO2 = 33 +/- 2 Torr) and during hypercapnia (60 +/- 2 Torr) in seven pentobarbital-anesthetized lambs. Analysis of variance showed that neither the magnitude of the hypoxic CBF response nor cerebral O2 consumption was significantly related to the level of arterial PCO2. To determine whether hypoxic cerebral vasodilation during hypercapnia was restricted by reflex sympathetic stimulation we studied an additional six hypercapnic anesthetized lambs before and after bilateral removal of the superior cervical ganglion. Sympathectomy had no effect on base-line CBF during hypercapnia or on the CBF response to hypoxic hypoxia. We conclude that the effects of hypoxic hypoxia on CBF and cerebral O2 consumption are not significantly altered by moderate hypercapnia in the anesthetized lamb. Furthermore, we found no evidence that hypercapnia results in a reflex increase in sympathetic tone that interferes with the ability of cerebral vessels to dilate during hypoxic hypoxia.

Animals↗

PubMed1988

Effect of PEEP and jugular venous compression on canine cerebral blood flow and oxygen consumption in the head elevated position.

Cerebral blood flow (CBF) (radiolabelled microspheres) and oxygen consumption (CMRO2) were studied in nine dogs during 30 min of either neck vein compression or application of positive end-expiratory pressure (PEEP) ventilation. With the animal in the prone position, elevation of the head from horizontal to 30 cm above the heart markedly decreased cisterna magna (PCSF) and dorsal sagittal sinus pressure (PCV). With the head elevated, compression of neck veins using neck tourniquet (pressure 40 mmHg) increased PCSF and PCV from 3.6 +/- 2.2 to 6.8 +/- 4.8 and -2.5 +/- 2.7 to 2.3 +/- 2.3 mmHg (mean +/- SE, P less than 0.05), respectively, while total or regional CBF and CMRO2 remained unchanged. Application of PEEP (15 cm H2O) increased right atrial pressure (-4.7 +/- 1.7 to -0.1 +/- 3.4 mmHg, P less than 0.05), but did not affect PCSF or PCV (3.4 +/- 3.3 to 3.3 +/- 3.7 and -3.5 +/- 2.6 to -4.1 +/- 2.4 mmHg, respectively, P greater than 0.05). Total or regional CBF and CMRO2 were also unaffected. These data demonstrate that, although neither maneuver affects CBF or CMRO2, neck vein compression elevates PCV above atmospheric pressure, but PEEP does not. In patients at risk for cerebral venous embolism, intermittent neck vein compression should be used as a prophylactic measure to prevent air embolism.

Animals↗