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Biomedical subjects

Sumio Hoka

Publications and source records attributed to Sumio Hoka.

At least 19 recordsLinked to original sources
PubMed2006

Nigral injection of antisense oligonucleotides to synaptotagmin I using HVJ-liposome vectors causes disruption of dopamine release in the striatum and impaired skill learning.

To produce an animal model of a dopa-responsive motor disorder with depletion of dopamine (DA) release in the striatum by dysfunction of the transmitter release machinery of the nigrostriatal DA system, we performed an intra-nigral injection of an HVJ-liposome gene transfer vector containing antisense oligodeoxynucleotides (ODNs) against synaptotagmin I (SytI), a key regulator of Ca(2+)-dependent exocytosis and endocytosis in adult rats. A unilateral intra-nigral injection of HVJ-liposome vectors containing antisense ODNs against SytI (syt-AS) caused a moderate disruption of methamphetamine-induced release of DA in the treated side of the striatum, while the syt-AS treatment did not affect physiological release of DA in the treated striatum. A bilateral intra-nigral injection of HVJ-liposome vectors containing syt-AS induced an impairment of the striatal DA-mediated acquisition of skilled behavior in a rotarod task without any deficits in general motor functions, such as spontaneous locomotor activity, motor adjusting steps, equilibrium function, or muscle strength. These findings suggest that an intra-nigral treatment with HVJ-liposome vectors containing syt-AS may cause a long-lasting nigral knockdown of SytI which, in turn, leads to a moderate dysfunction of the DA release machinery in the terminals of the nigrostriatal DA system and a subsequent mild depletion of DA release in the striatum.

Analysis of Variance↗
PubMed2006

Differential localization and regulation of stargazin-like protein, gamma-8 and stargazin in the plasma membrane of hippocampal and cortical neurons.

Transmembrane AMPA receptor regulatory proteins (TARPs), including stargazin/gamma-2, are associated with AMPA receptors and participate in their surface delivery and anchoring at the postsynaptic membrane. TARPs may also act as a positive modulator of the AMPA receptor ion channel function; however, little is known about other TARP members except for stargazin/gamma-2. We examined the synaptic localization of stargazin/gamma-2 and gamma-8 by immunoelectron microscopy and biochemical analysis. The analysis of sodium dodecyl sulfate-digested freeze-fracture replica labeling revealed that stargazin/gamma-2 was concentrated in the postsynaptic area, whereas gamma-8 was distributed both in synaptic and extra-synaptic plasma membranes of the hippocampal neuron. When a synaptic plasma membrane-enriched brain fraction was treated with Triton X-100 and separated by sucrose density gradient ultracentrifugation, a large proportion of NMDA receptor and stargazin/gamma-2 was accumulated in raft-enriched fractions, whereas AMPA receptor and gamma-8 were distributed in both the raft-enriched fractions and other Triton-insoluble fractions. Phosphorylation of stargazin/gamma-2 and gamma-8 was regulated by different sets of kinases and phosphatases in cultured cortical neurons. These results suggested that stargazin/gamma-2 and gamma-8 have distinct roles in postsynaptic membranes under the regulation of different intracellular signaling pathways.

Animals↗
PubMed2006

Spinal anesthesia using a continuous spinal catheter for cesarean section in a parturient with prior surgical correction of scoliosis.

This case report demonstrates the successful anesthetic management of cesarean section for a 29-year-old primiparous parturient with a past history of a scoliosis operation at 13 years of age. An Isola hook and screw-rod system had been implanted as posterior spinal instrumentation at the level of T3-L3. We titrated hyperbaric bupivacaine 7 mg combined with fentanyl 15 microg through a continuous spinal catheter, placed with a catheter-over-needle technique in order to avoid unintentional wide spread of anesthetic agents. The anesthetic level was T4 at the start of the operation. Her surgery was carried out without any problems. Headache, as a dural tap-related complication, was not observed. Spinal anesthesia with the titration of anesthetic agents for cesarean section is considered to be one of the choices for a parturient who has had spinal instrumentation.

Adult↗
PubMed2006

Anesthetic management of a patient with a history of Batista procedure for dilated cardiomyopathy undergoing gastric surgery.

We experienced anesthetic management for an operation to remove a hemorrhagic gastric submucosal tumor in a patient who had undergone left ventricular volume reduction (the Batista procedure) for dilated cardiomyopathy (DCM) 2 years previously. Preoperative evaluations indicated the relapse of severe DCM. Intravenous and epidural anesthesia was employed with the aid of an intraaortic balloon pump (IABP). Safe anesthetic management was achieved under the guidance of a Swan-Ganz catheter without inducing overreduction of afterload or excessive preload.

Anesthesia, Epidural↗
PubMed2006

Sumatriptan alleviates pain in patients with trigeminal neuralgia.

OBJECTIVES: Arterial compression of the trigeminal root may lead to trigeminal neuralgia. 5-HT1B/1D receptor agonists may inhibit vasodilation and inflammation near the irritated trigeminal root. A recent study showed attenuation of mechanical allodynia by a 5-HT1A receptor agonist in a rat model of trigeminal neuralgia. The present study examined the effectiveness of a 5-HT1A/1B/1D receptor agonist, sumatriptan, on pain relief in patients with trigeminal neuralgia. METHODS: The study was conducted in 15 patients with idiopathic trigeminal neuralgia. The patients had been suffering from painful paroxysms for at least 1 month. Each patient was injected with 1 mL of saline subcutaneously (placebo), followed 15 minutes later with subcutaneous sumatriptan (3 mg in 1 mL saline). This was followed the next day by oral sumatriptan (50 mg twice daily) for 1 week. RESULTS: The visual analog scale did not change after saline, but significantly decreased after subcutaneous sumatriptan. Both 1 week after oral sumatriptan and 1 week after discontinuation of the drug, visual analog scale scores resulted in a significant decrease from the baseline. Adverse events after subcutaneous sumatriptan occurred in 4 patients: fatigue in 4 and nausea in 2. Side effects from the oral medication appeared in 4 patients: fatigue in 2, nausea in 1 and chest discomfort in 1. These side effects subsided soon after discontinuation of sumatriptan. CONCLUSIONS: Our results indicate that subcutaneous injection followed by oral administration of sumatriptan produces prompt and continuous analgesia in patients with trigeminal neuralgia.

Adult↗
PubMed2006

Subcutaneous sumatriptan for refractory trigeminal neuralgia.

BACKGROUND: Mechanical compression of the trigeminal root by an artery is thought to cause trigeminal neuralgia. The 5-HT(1B/1D) receptor agonist may inhibit neurogenic inflammation and vasodilation near the irritated trigeminal root. OBJECTIVE: To examine the effectiveness of a 5-HT(1B/1D) receptor agonist, sumatriptan, on a paroxysmal pain in trigeminal neuralgia. METHODS: Twenty-four patients with trigeminal neuralgia refractory to previous treatment were randomized to receive subcutaneously either 3 mg (1 mL) of sumatriptan or 1 mL of saline placebo. Following a 7-day period, patients crossed over to receive the alternative treatment. Paroxysmal pain triggered by touching or moving the face was assessed with VAS before and 15 minutes after the treatment. Patients used a descriptive scale to pain-grade outcome, and asked to note whether the pain returned and how long after therapy it recurred. RESULTS: Subcutaneous sumatriptan, but not placebo, significantly decreased VAS from 8.3 +/- 2.1 to 2.4 +/- 3.0 cm (mean +/- SD). The number of patients who described their pain as moderately or slightly better was 20 in the sumatriptan group and 1 in the placebo group. The effect of subcutaneous sumatriptan persisted for a median period of 7.9 hours (range: 1-20 hours). CONCLUSIONS: Subcutaneous sumatriptan produced prompt analgesia without serious adverse reactions in patients with trigeminal neuralgia refractory to previous treatment.

Adult↗
PubMed2006

A comparison of epidural blockade produced by plain 1% lidocaine and 1% lidocaine prepared by dilution of 2% lidocaine with the same volume of saline.

Local anesthetics are commonly diluted with saline, but the influence of the dilution on the epidural anesthesia remains unclear. We randomized 40 patients scheduled for gynecological abdominal surgery under epidural anesthesia to one of two groups; those in group P received plain commercially prepared 1% lidocaine and those in group D received 1% lidocaine derived from 2% lidocaine and the same volume of saline was infused epidurally with an epidural catheter at L1-2. The pH and sodium and chloride ion concentrations of the solutions were measured. Sensory and motor blockade, foot skin temperature, arterial blood pressure, and heart rate were assessed at 5, 10, and 15 min after the epidural infusion. The spread of sensory blockade was significantly wider in group P at all assessment times than in group D. The increase of foot temperature and decrease of mean arterial blood pressure were significantly faster in group P than in group D. Although the mean pH values of the two solutions were similar, sodium and chloride ion concentrations of the diluted solution were significantly larger than those of the plain solution. We conclude that 2% lidocaine diluted with the same volume of saline produces less potent epidural blockade than commercially prepared plain 1% lidocaine.

Anesthesia, Epidural↗
PubMed2006

Activities of rat cytochrome P450 3A and 2C isoforms are increased in vivo by magnesium sulfate as evidenced by enhanced oxidation of bupivacaine and testosterone in liver microsomes.

We previously reported that magnesium sulfate (MgSO(4)) increases the threshold dose of bupivacaine in inducing seizure in rats. Cytochrome P450 (P450) isoforms involved in the biotransformation of bupivacaine to three oxidative metabolites and the effects of MgSO(4) in vivo on the P450 activities in rats were investigated. Of six cDNA-expressed rat P450 isoforms tested, CYP3A2 and CYP2C11 had high rates for N-debutlylation and 3'-hydroxylation of bupivacaine, respectively. The liver microsomes prepared from male rats pretreated with intravenous administration of MgSO(4) (a bolus dose of 25 mg/kg, followed by infusion of 2.0 mg/kg/min for 6 h) showed increased V(max) values for N-debutylation and 3'-hydroxylaiton of bupivacaine compared to the liver microsomes from control rats. Administration of MgSO(4) also increased the activities of testosterone 6beta- and 16alpha-hydroxylation. Although the level of expression of CYP3A and CYP2C isoforms in the liver microsomes were unchanged, NADPH-P450 reductase and cytochrome b(5) were found to be induced by intravenous administration of MgSO(4). These results suggest that CYP3A and CYP2C isoforms are activated by MgSO(4) in vivo as a consequence of enhanced microsomal electron transfer due to induction of NADPH-P450 reductase and cytochrome b(5), leading to the increased metabolism and clearance of bupivacaine.

Anesthetics, Local↗
PubMed2006

[Anesthetic management for a patient with severely obstructed upper airway undergoing CO2 laser resection of the tracheal tumor].

A 76-year-old woman was scheduled to undergo a laser resection of the tracheal tumor which severely obstructed the upper airway. She had a past history of thoracic aortic aneurysm resection and myocardial infarction. After spraying the patient's oral cavity with 8% lidocaine, a laryngeal mask airway was inserted under spontaneous respiration. Tumor resection was successfully performed using CO2 laser through the laryngeal mask airway with the aid of low dose fentanyl under spontaneous respiration. Maintaining FIO2 at 0.5 could prevent hypoxemia. Although mild edema was observed in the larynx at the completion of the surgery, the patient achieved remarkable improvement in her breathing status. Consequently, she was able to undergo radiotherapy on the 5th postoperative day. This effectively reduced the tumor volume.

Aged↗
PubMed2005

Impaired acquisition of skilled behavior in rotarod task by moderate depletion of striatal dopamine in a pre-symptomatic stage model of Parkinson's disease.

In view of recent findings that suggest that the nigrostriatal dopamine (DA) system plays a role in motor control and the acquisition of habits and skills, we hypothesized that the striatum-based function underlying the acquisition of skilled behaviors might be more vulnerable to dopamine depletion than the motor control. To test this hypothesis, we investigated whether impaired acquisition of skilled behaviors occurs in a pre-symptomatic stage model of Parkinson's disease (PD). By using the microdialysis method and the 6-OHDA-technique to destroy dopamine neurons, we confirmed that rats with unilateral partial lesions of the nigral dopamine cells by 6-OHDA are suitable for a pre-symptomatic stage model of Parkinson's disease. The rats in this model exhibited moderate disruption of striatal dopamine release function and relatively intact motor functions. In a rotarod test, the impaired acquisition of skilled behavior occurred in rats with bilateral partial lesions of the nigral dopamine cells by 6-OHDA. These rats displayed intact general motor functions, such as locomotor activity, adjusting steps, equilibrium function and muscle strength. Based on these results, we concluded that the striatum-based function underlying the acquisition of skilled behaviors or sensorimotor learning may be more vulnerable to dopamine depletion than the motor control.

Amphetamine↗
PubMed2005

Rapid injection of epidural mepivacaine speeds the onset of nerve blockade.

PURPOSE: When used intraoperatively, mepivacaine can produce a satisfactory sensory block. However, insufficient information is available concerning the factors that affect the speed of nerve blockade with epidural analgesia. The optimal rate of injection of mepivacaine has not been determined. We examined whether the speed of epidural infusion of mepivacaine affects the speed of nerve blockade. METHODS: Forty patients, physical status ASA I-II, scheduled for gynecological abdominal surgery, were enrolled in this double blind randomized trial. A catheter was inserted 4 cm in the epidural space in the midline at L1-L2. Three minutes after a test dose of 2 mL plain 1% mepivacaine over four seconds, 8 mL were injected epidurally at a rate of 1 mL.sec(-1) (fast group) or 0.05 mL.sec(-1) (slow group). Sensory and motor blockade, blood pressure, and heart rate were assessed at five, ten, and 15 min after the epidural injection. RESULTS: There was a significant difference in the spread of sensory blockade at five minutes after the epidural injection between the two groups, but not at ten and 15 min. Blood pressure decreased at five and ten minutes, recovered at 15 min in the fast group, and remained stable in the slow group. CONCLUSION: Rapid injection of mepivacaine in the epidural space produced a more rapid onset of epidural block than slow injection, but there was no difference in the final extent of the block.

Adult↗
PubMed2005

General anesthesia for patients with Brugada syndrome. A report of six cases.

PURPOSE: To review six cases of Brugada syndrome presenting for insertion of a cardioverter-defibrillator under general anesthesia. CLINICAL FEATURES: All patients had a history of syncope, ST segment elevation in the right precordial lead of the electrocardiogram (ECG) which became prominent after a pilsicainide challenge test. Routine monitors, right precordial lead of the ECG and an external defibrillator were installed prior to anesthesia. We administered propofol/midazolam for induction, and propofol/sevoflurane combined with fentanyl for maintenance of anesthesia. Atropine and ephedrine were administered to decrease vagal tone. No ECG change or arrhythmia was observed perioperatively. After the successful implantation of the defibrillator, all patients were discharged without any adverse event. CONCLUSION: By avoiding agents or conditions that may exacerbate Brugada syndrome during anesthesia, we were able to manage the patients uneventfully for implantation of a cardioverter-defibrillator.

Anesthesia, General↗
PubMed2005

Noninvasive assessment of left ventricular pressure-area relationship using transesophageal echocardiography and tonometry during cardiac and abdominal aortic surgery.

PURPOSE: The purpose of this study was to noninvasively evaluate intraoperative left ventricular (LV) performance by an online pressure-area relationship using transesophageal echocardiography (TEE) and tonometry. METHODS: In study 1, LV pressure with a micromanometer catheter, LV cross-sectional area with TEE, direct radial pressure, and tonometric arterial pressure were simultaneously recorded in 5 patients (10 measurements) undergoing cardiac surgery. End-systolic elastance (E'es) was determined from pressure-area loops during inferior vena caval (IVC) occlusion. In study 2, in 16 patients undergoing repair of abdominal aortic aneurysm, LV performance (E'es; effective arterial load, E'a, and LV end-diastolic area, LV-EDA) was examined by noninvasive assessment of pressure-area loops using TEE and tonometry at aortic cross-clamping and unclamping. RESULTS: E'es by tonometric arterial pressure closely correlated with E'es by LV pressure (r = 0.92) in study 1. E'es at aortic clamping were not significantly different from those at unclamping. The clamping increased LV-EDA and E'a by approximately 13% and 44%, and the unclamping significantly decreased by 9% and 22%, respectively. CONCLUSION: Our results demonstrated that online tonometric arterial pressure and LV area measured by automated border detection (ABD) of TEE might be used to calculate E'es to estimate LV contractility and allow the estimation of LV performance during aortic clamping and unclamping.

Aged↗
PubMed2005

Patient-controlled epidural analgesia during labor using ropivacaine and fentanyl provides better maternal satisfaction with less local anesthetic requirement.

PURPOSE: To test the hypothesis that patient-controlled epidural analgesia (PCEA) using ropivacaine and fentanyl provides better maternal satisfaction and less anesthetic requirement than conventional continuous epidural infusion (CEI) during labor, we studied 58 uncomplicated parturients (singleton, vertex presentation). METHODS: After establishing effective epidural analgesia with 11 ml of 0.2% ropivacaine, all parturients were randomly divided into one of two groups: the PCEA group (n = 29) or the CEI group (n = 29). In the PCEA group, the pump was initiated to deliver a basal infusion at 6 ml x h(-1) and a demand dose of 5 ml; the lockout interval was 10 min, and there was a 31 ml x h(-1) limit. The drugs used were 0.1% ropivacaine + fentanyl 2 microg x ml(-1). In the CEI group, epidural analgesia was maintained with the same solution as the PCEA group at a constant rate of 10 ml x h(-1). If parturients requested additional analgesia in the CEI group, we added 8 ml of epidural 0.2% ropivacaine without fentanyl. RESULTS: Parturients' demographic data, such as duration of labor, mode of delivery, Apgar score, and umbilical arterial pH did not differ between the two groups. However, the hourly requirement of ropivacaine was significantly less in the PCEA group than in the CEI group (9.3 +/- 2.5 vs. 17.6 +/- 7.6 mg x h(-1); P < 0.05). Parturients' satisfaction assessed by the Visual Analogue Scale tended to be higher in the PCEA group than in the CEI group. Side effects such as nausea, hypotension, and itching were similar for the two groups. CONCLUSION: We found that PCEA was an effective means of providing optimal analgesia, with better satisfaction during labor and less local anesthetic requirement.

Adult↗
PubMed2005

Determination of oxycodone and hydrocotarnine in cancer patient serum by high-performance liquid chromatography with electrochemical detection.

We developed an HPLC procedure using electrochemical detection for the quantitation of oxycodone and hydrocotarnine in cancer patients serum. An eluent of methanol:acetonitrile:5 mM pH 8 phosphate buffer (2:1:7) was used for the mobile phase. The calibration curve was linear in the range from 10 ng/mL to 100 ng/mL. The recovery of oxycodone and hydrocotarnine was 97.2% and 90.5%, respectively. The relative standard deviations within-runs and between-runs for the assay of oxycodone or hydrocotarnine were less than 4.8%. The method developed here was better than the method reported previously.

Analgesics, Opioid↗
PubMed2005

[Effectiveness of ropivacaine and fentanyl for postoperative epidural analgesia following thoracic surgery].

BACKGROUND: Epidural ropivacaine is now a common drug used for postoperative analgesia. However, little information is available concerning regression of sensory blockade and analgesia following prolonged epidural infusion of ropivacaine. We investigated the efficacy of ropivacaine and fentanyl for postoperative analgesia after thoracic surgery. METHODS: Thirty patients undergoing thoracic surgery were enrolled. After surgery with general and thoracic epidural anesthesia, continuous epidural infusion of 0.2% ropivacaine+fentanyl (1.67 microg x ml(-1)) was started at a rate of 6 ml x h(-1) for patients whose height was more than 155 cm and 4 ml x h(-1) for those below 155 cm with possibility of an additional bolus injection of 3 ml at least every 60 min. RESULTS: An additional epidural injection of 3 ml produced a decrease in VAS without significant changes of vital signs. The greatest VAS was 10+/-25 mm in the incision site and 36+/-38 mm in the ipsilateral shoulder. Sensory blockade was sustained until the morning after the day of surgery. Also blood pressure and heart rate were stable throughout the observation period. There were no adverse effects except for slight nausea in three patients. CONCLUSIONS: A bolus of 3 ml with continuous 4-6 ml x h(-1) epidural injection of ropivacaine plus a small dose of fentanyl would decrease postoperative pain with stable vital signs in patients after thoracic surgery.

Aged↗
PubMed2005

[Advantage of ropivacaine for postoperative epidural analgesia following leg orthopedic surgery].

BACKGROUND: Epidural administration of local anesthetics may lead to effective pain relief. However, tachyphylaxis or other problems following prolonged epidural anesthesia may develop and in many cases difficulties exist in the maintenance of the similar degree of sensory blockade. The present study was therefore performed to investigate the analgesic effect of continuous postoperative epidural infusion of ropivacaine with fentanyl in comparison with that of bupivacaine or ropivacaine alone. METHODS: After leg orthopedic surgery with lumbar combined spinal-epidural anesthesia, thirty-six patients were randomized to one of the three postoperative epidural infusion groups: bupivacaine 0.125%, ropivacaine 0.2%, or ropivacaine 0.2% with 2.2 microg x ml(-1) (400 microg x 180 ml(-1)) of fentanyl. Continuous epidural infusion was started at a rate of 6 ml x h(-1) with possibility of an additional bolus injection of 3 ml at least every 60 min. Pain was assessed using a 10-cm visual analog scale (VAS) just before and 15 min after epidural bolus injections, and 15-20 h after the start of continuous epidural infusion as the severe at pain through the observation. The spread of analgesia (loss of sharpness in pinprick perception) and motor block (Bromage scale) were evaluated bilaterally. Systolic and diastolic blood pressure and heart rate were also measured. RESULTS: The epidural bolus infusion was associated with a significant decrease of VAS (P < 0.001) and stable blood pressure and heart rate in all groups. The maximal VAS in patients receiving 0.2% ropivacaine+fentanyl was significantly less compared to that in the other two groups. The regression of sensory blockade was significantly prolonged in patients treated with ropivacaine+fentanyl. There was no significant difference in the spread of sensory analgesia between 20 min and 15-20 h after the continuous epidural anesthesia in this group. None of the patients developed adverse effects such as respiratory depression, nausea, and pruritus. CONCLUSIONS: Epidural injection of ropivacaine with fentanyl decreased postoperative pain with stable vital signs in patients undergoing leg orthopedic surgery, as compared to bupivacaine or ropivacaine alone, possibly because of the maintenance of sensory blockade by ropivacaine and enhancement of this sensory blockade by fentanyl.

Adult↗