Search PubMed⌕ Search

Biomedical subjects

Y Okuda

Publications and source records attributed to Y Okuda.

At least 127 records · Page 7Linked to original sources
PubMed1999

[A case of cardiac arrest after torsades de pointes due to prolonged QT interval syndrome possibly associated with subarachnoid hemorrhage].

An 58-year-old woman with prolonged QT interval syndrome possibly associated with subarachnoid hemorrhage underwent clipping for cerebral artery aneurysm. Anesthesia was induced with diazepam, fentanyl and vecuronium, and maintained with nitrous oxide (66%)-oxygen and sevoflurane (1%) with fentanyl. However, three hours after the start of operation, torsades de pointes suddenly appeared and cardiac arrest was followed. After cardiopulmonary resuscitation, sinus rhythm was restored. At that time, serum potassium was decreased to 2.7 mEq.l-1. Five days after the operation, she died despite cardiopulmonary resuscitation for frequent episodes of ventricular tachycardia including torsades de pointes. Ventricular tachycardia including torsades de pointes may have been caused by decreased serum potassium.

Anesthesia, General↗
PubMed1999

[Caesarean section in a patient with a history of HELLP syndrome].

A 36-year-old woman underwent emergency caesarean section following the diagnosis of HELLP syndrome. Four years earlier, after having undergone the same procedure for HELLP syndrome, she had experienced hypovolemic shock, renal failure, and disseminated intravascular coagulopathy during the postoperative period. This time, the patient showed bleeding, elevation of liver enzymes (ALT, AST, LDH) and a reduction of antithrombin III activity in the 36th week of pregnancy. Anesthesia was induced by thiamylal 4 mg.kg-1 and suxamethonium 1 mg.kg-1 and after delivery maintained by oxygen-nitrous oxide-isoflurane, and all procedures were performed without any incident. No major complications such as intraperitoneal bleeding, renal failure, or disseminated intravascular coagulopathy occurred during the postoperative period. It is suggested that caesarean section should be carried out as soon as possible after the diagnosis of HELLP syndrome is confirmed.

Adult↗
PubMed1999

[Total intravenous anesthesia with propofol, fentanyl and ketamine for carotid endarterectomy under somatosensory evoked potential monitoring--combination with intraoperative hypothermia].

We reported anesthetic management combined with hypothermia for carotid endarterectomy under somatosensory evoked potential monitoring. Anesthesia was induced by propofol, fentanyl and ketamine, and maintained by infusion of propofol and ketamine and intermittent injections of fentanyl. Perioperative hypothermia was induced by gradually reducing the temperature of a circulating water mattress underneath the body to 15 degrees C. Additionally, somatosensory evoked potential monitoring was performed and recordings were obtained immediately after induction of anesthesia, and before as well as during cross-clamping of the internal carotid artery. Rectal temperature was reduced to 33.7 degrees C when cross-clamping of carotid artery was carried out, but major changes between before and during the procedure was not observed. All procedures were done uneventfully and gradual rewarming was accomplished by electric blanket. No neurological deficits were observed following recovery from anesthesia. Total intravenous anesthesia with propofol, fentanyl and ketamine may be useful for carotid endarterectomy under hypothermia and somatosensory evoked potential monitoring. This method may provide neuronal protection against ischemia injuries induced by cross-clamping of the carotid artery.

Aged↗
PubMed1999

[Differential lung ventilation using Fogarty catheter after accidental damage of bronchial blocker cuff].

We performed differential lung ventilation using a Fogarty catheter after accidental damage of a bronchial blocker. A 57-year-old-man underwent thoracoscopic surgery for right pneumothorax. Anesthesia was induced with fentanyl and midazolam, and maintained with propofol and continuous epidural block with 2% mepivacaine. We used a single lumen endotrachial tube with a bronchial blocker for differential lung ventilation. We inserted the tip of the bronchial blocker into the right bronchus under fiberoptic broncoscopy after the patient had been placed in the lateral position. Four milliliters of air were injected into the bronchial blocker cuff before inserting the thoracoscope and differential lung ventilation was started. The right lung expanded suddenly because of accidental damage of the cuff one hour after starting surgery. We inserted a Fogarty catheter (10 Fr.) into the right bronchus under fiberoptic broncoscopy. Its balloon was inflated for differential lung ventilation. The procedure was performed successfully and uneventfully. We conclude that Fogarty catheter is an effective replacement for a damaged bronchial blocker cuff during differential lung ventilation.

Catheterization↗
PubMed1999

[Anesthetic management for transtracheal placement of a catheter for intracavity infusion of an antifungal drug in patients with pulmonary fungus ball of aspergillosis].

A catheter was inserted through the cricothyroid membrane under general anesthesia using a laryngeal mask airway in two patients with pulmonary fungus ball of aspergillosis to administer an antimycotic into the fungus ball. Anesthesia was induced with fentanyl and propofol in both patients. The laryngeal mask airway was inserted using intravenous injection of vecuronium. Anesthesia was maintained with continuous infusion of propofol. The catheter was inserted through the cricothyroid membrane and placed in the pulmonary fungus ball using bronchoscope. Perioperative and postoperative courses were uneventful in both patients. It was concluded that the laryngeal mask airway is useful for airway management when a catheter is inserted into a pulmonary fungus ball through the cricothyroid membrane.

Aged↗
PubMed1999

[Anesthetic management of a patient with dilated cardiomyopathy under total intravenous anesthesia with propofol and ketamine combined with continuous epidural analgesia].

We report our experience with total intravenous anesthesia (TIVA) with propofol and ketamine combined with continuous epidural analgesia in a 72-year-old-male patient with dilated cardiomyopathy scheduled for a total prostatectomy. After premedication with atropine 0.5 mg and pethidine 35 mg, anesthesia was induced with ketamine 50 mg, fentanyl 0.1 mg and using a step down method of propofol (6-->4-->2 mg.kg-1.hr-1). After hemodynamic parameters had been stabilized, the trachea was intubated. Then, 1.5% lidocaine 6 ml was injected through an epidural catheter, placed at the L 1-2 intervertebral space. Anesthesia was maintained with continuous infusion of propofol 1 mg.kg-1.hr-1 and ketamine 1 mg.kg-1.hr-1, and continuous epidural analgesia with 1.5% lidocaine 2 ml.hr-1. Hemodynamics remained stable throughout the operative procedure. No postoperative complications occurred. TIVA with propofol and ketamine in combination with epidural analgesia is useful for patients with dilated cardiomyopathy in order to maintain stable hemodynamics during anesthesia.

Aged↗
PubMed1999

[Anesthetic management for urgent endoscopy in a child with heterotopic liver transplant].

A 6-year-old boy with heterotopic liver transplant underwent urgent endoscopy under general anesthesia because of bloody stool. He was taking cyclosporin as an immunosuppressant. His hepatic function was normal and no side effects of cyclosporin were observed. Preoperative blood transfusion was performed because of severe anemia. Anesthesia was induced with midazolam 2 mg, ketamine 20 mg and fentanyl 0.05 mg, and maintained with addition of midazolam and ketamine. We did not use any inhalation anesthetics to avoid postoperative hepatic dysfunction. The endoscopy was successfully performed and the postoperative course was uneventful. We conclude that preanesthetic evaluation of immunosuppressant state and the hepatic function of transplanted liver is important for anesthetic management of a patient with heterotopic liver transplant.

Anesthesia, General↗
PubMed1999

[A patient uninformed about his illness became aware of his lung cancer when an anesthesiologist visited him for pain control].

Much has been said about the importance of informed consent in Japan, but informing cancer to the patient has not been popular so far. We, as anesthesiologists, often treat pain in cancer patients, who occasionally, are not informed about the cancer. And we sometimes have patients with whom cautious consulting is necessary. This report presents our experience with a patient uninformed about the cancer but suspicious of his lung cancer. We met him as anesthesiologists, and this made the patient convinced that he had a cancer and was about to die soon.

Adult↗
PubMed1998

Effect of a topically applied neutralizing antibody against vascular endothelial growth factor on corneal allograft rejection of rat.

BACKGROUND: Studies in corneal transplant rejection remain important because acute immunologic rejection continues to be the leading cause of human corneal transplant failure. As the permeability of vessels and the neovascularization induce cells infiltration into the graft, we considered the possibility that vascular endothelial growth factor (VEGF), a potent permeability-increasing factor and angiogenesis-mediating factor, could participate in the immune response. METHODS: As the established corneal transplant model for rejection, the corneal transplant between Lewis and Fisher rats has been reported. First, we evaluated VEGF production in the graft by immunohistochemical method in the animal model. Next, we tried to neutralize the effect of VEGF by topical administration of anti-VEGF antibody. We administered anti-VEGF antibody as eye drops for 10 days just after the transplantation of the established animal corneal transplant model. RESULTS: VEGF was strongly produced from the infiltrative cells into the graft. Anti-VEGF antibody significantly suppressed the acute rejection compared with saline or rabbit IgG. CONCLUSIONS: The inhibition of VEGF by topically applied neutralizing antibody is a new potential therapeutic strategy for the treatment of corneal transplantation.

Administration, Topical↗
PubMed1998

Inhibitory effects of dehydrozingerone and related compounds on 12-O-tetradecanoylphorbol-13-acetate induced Epstein-Barr virus early antigen activation.

Dehydrozingerone, 4-(4-hydroxy-3-methoxyphenyl)-3-buten-2-one, is half an analog of curcumin which is known to have anti-tumor activity. The anti-tumor promoting activity of dehydrozingerone was evaluated by determining the inhibitory effect on Epstein-Barr virus early antigen (EBV-EA) activation induced by 12-O-tetradecanoylphorbol-13-acetate (TPA). The concentration needed for 50% inhibition of the tumor promotion (IC50) of dehydrozingerone was similar to that of curcumin. To elucidate the structure-activity relationship on the anti-tumor promoting activity, dehydrozingerone, curcumin, isoeugenol, which has no carbonyl group in the side chain, benzalacetone, which is the basic structure of dehydrozingerone, o-dehydrozingerone, which is the ortho-hydroxyl substituted compound of dehydrozingerone, and their related compounds were investigated using the in vitro short-term assay on TPA-induced EBV-EA activation. o-Dehydrozingerone showed the most potent inhibitory effect in a series of tested dehydrozingerone derivatives and their related monosubstituted benzalacetones. This suggests that the occupation at both ortho positions of the hydroxyl group enhances the anti-tumor promoting activity. Isoeugenol inhibited the tumor promoting activity at a concentration of about one-third of the IC50 of dehydrozingerone. This indicates that the carbonyl group in the side chain has a negative impact on the anti-tumor promoting activity. The inhibitory effects of the carbon-carbon bond in the side chain were studied using benzylacetone with a single bond, benzalacetone with a double bond and 4-phenyl-3-butyn-2-one with a triple bond. 4-Phenyl-3-butyn-2-one inhibited the most potent activity followed by benzalacetone and benzylacetone.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1998

Omega-3 polyunsaturated fatty acids--modulation of voltage-dependent L-type Ca2+ current in guinea-pig tracheal smooth muscle cells.

Omega-3 polyunsaturated fatty acids have been reported to be associated with favorable changes in the respiratory system. To determine one of the mechanisms for this effect, membrane currents were recorded in guinea-pig tracheal myocytes by using the whole-cell voltage clamp technique. Without EGTA in the patch pipette containing the Cs-internal solution, command voltage pulses positive to +0 mV from a holding potential of -60 mV elicited a voltage-dependent L-type Ca2+ current (I(Ca x L)) and a subsequent outward current. Upon repolarization, slowly decaying inward tail currents were recorded. The outward currents and the inward tail current were enhanced by methyl-1,4,-dihydro-2,6-dimethyl-3-nitro-4-(2-trigluromethylphenyl )-pyridine-5-carboxylate, and blocked by Cd2+ or nifedipine. Inclusion of EGTA (5 mM) in the patch pipette also abolished these currents, indicating that they were Ca2+-dependent. When [Cl-]o or [Cl-]i was changed, the reversal potential of these currents shifted, thus behaving like a Cl(-)-sensitive ion channel. 4,4'-Diisothiocyanatostilbene-2,2'-disulphonic acid. a Cl- channel blocker, inhibited the currents. The omega-3 polyunsaturated fatty acids eicosapentaenoic acid (3-30 microM) and docosahexaenoic acid (30 microM) suppressed I(Ca x L) and then inhibited I(Ca x Cl) in a reversible manner. Similar inhibitory effects of eicosapentaenoic acid on I(Ca x L) were observed with 5 mM EGTA in the patch pipette. Neurokinin A (1 microM) and caffeine (10 mM) also transiently activated I(Cl x Ca), probably due to Ca2+ release from Ca2+ storage sites. Pretreatment of the cells with eicosapentaenoic acid markedly suppressed the activation of I(Cl x Ca) by neurokinin A or caffeine. These results suggest that omega-3 polyunsaturated fatty acids inhibit voltage-dependent L-type Ca2+ currents and also Ca2+-activated Cl- currents in tracheal smooth muscle cells from the guinea-pig, which may play a role in modulation of tracheal smooth muscle tone.

Animals↗
PubMed1998

The pattern of cytokine gene expression in lymphoid organs and peripheral blood mononuclear cells of mice with experimental allergic encephalomyelitis.

We previously observed Th1-dominated response in the central nervous system (CNS) of mice during the course of experimental allergic encephalomyelitis (EAE) with a semiquantitative reverse transcriptase-polymerase chain reaction (RT/PCR) analysis. We report here that mRNA levels for both inflammatory cytokines including interleukin (IL)-1beta, IL-2, IL-6, interferon (IFN)-gamma, tumor necrosis factor (TNF)-alpha and TNF-beta and immunoregulatory cytokines including IL-4, IL-10 and transforming growth factor (TGF)-beta were up-regulated in the preclinical and/or acute phase but down-regulated in the recovery phase of EAE in lymph node (LN) of mice. Similar profiles for cytokine mRNA levels were also observed in spleen and peripheral blood mononuclear cells (PBMC). The present study also showed that a significant down-regulation of the mRNA level for IL-6 in the acute phase as compared with the preclinical phase, and a significant reduction of the mRNA level for TGF-beta in the preclinical and acute phase as compared with the corresponding mRNA levels in the control mice treated with complete Freund's adjuvant alone were characteristic in peripheral immune organs of mice with EAE. These results indicate that no particular bias in cytokine production occurred in peripheral immune organs of mice with actively induced relapsing EAE, and that the relative reduction in production of TGF-beta or IL-6 in peripheral circulation might participate in the induction or remission of EAE, respectively. Our results using the animal model of multiple sclerosis (MS) suggested that the mRNA levels for IL-6 and TGF-beta in PBMC from patients with MS may be a good indicator to assess the disease activity or to predict relapse.

Animals↗
PubMed1998

High concentration of glucose causes impairment of the function of the glutathione redox cycle in human vascular smooth muscle cells.

We demonstrated that high glucose reduced H2O2 scavenge activity in human vascular smooth muscle cells. In the cells exposed to high glucose, the intracellular glutathione content decreased, although the NADPH content was unchanged. The rate of uptake of cystine, which is a rate-limiting precursor of the glutathione synthesis, decreased in the high glucose group compared with the control group. These decreases were shown to be dependent on glucose concentration. It was suggested that high glucose causes impairment of the function of the glutathione redox cycle in human vascular smooth muscle cells, resulting in reduced H2O2 scavenge activity.

Aorta↗
PubMed1998

Portal vein reconstruction with conventional polytetrafluoroethylene grafts: an experimental study in dogs.

The purpose of this study was to examine the short- and long-term performance of conventional polytetrafluoroethylene (PTFE) grafts for portal vein reconstruction. The grafts were placed as a portal vein replacement in 11 mongrel dogs. At 1 month and 6 months, the grafts were then retrieved and examined for patency, while also undergoing a pathological analysis. During the observation period (at 55 days), one dog died of an unknown cause with a patent graft. The patency rates of the other 10 grafts were 83% (5/6) at 1 month and 100% (4/4) at 6 months. However, the neointima formation was incomplete even 6 months after implantation. In conclusion, although conventional PTFE grafts may be used as a synthetic alternative to autogenous vein grafts, every effort should be made to use autogenous vein grafts before considering conventional PTFE grafts.

Animals↗
PubMed1998

Influence of cellular incorporation of n-3 eicosapentaenoic acid on intracellular Ca2+ concentration and membrane potential in vascular smooth muscle cells.

Long-term treatment with n-3 eicosapentaenoic acid (EPA) has been shown to exert hypotensive effects and have beneficial effects on atherosclerosis. To elucidate one of the underlying mechanisms of these effects, intracellular calcium concentration [Ca2+]i, and resting membrane potential were measured in rat vascular smooth muscle cells (A7r5 cell) treated with EPA, using Ca2+-sensitive dye fura-2 AM and the patch clamp technique. The alterations in fatty acid compositions of phospholipids and cell migration after treatment with EPA (30 microM) for 6 h-7 days were also examined. After treating cells with EPA, the EPA and DPA (docosapentaenoic acid) content of the phospholipid fraction (mol.%) increased in a time-dependent manner. Alternatively, arachidonic acid (AA) decreased, and then the ratio of EPA and AA (EPA/AA) increased significantly. The resting [Ca2+]i decreased from 170 +/- 46 nM (n = 16) in control cells to 123 +/- 29 nM (n = 16) in cells treated with EPA (30 microM) for 7 days. Vasopressin (100 nM), endothelin-1 (100 nM) and platelet-derived growth factor (PDGF 5 ng/ml) evoked an initial peak of [Ca2+]i, followed by a smaller sustained rise of [Ca2+]i in the presence of extracellular Ca2+. In EPA-treated cells, both the peak and the sustained rise of [Ca2+]i induced by these agonists decreased in comparison to the control cells. EPA treatment also decreased the transient [Ca2+]i rise evoked by these agonists in the absence of extracellular Ca2+. Under the current clamp condition, resting membrane potential was significantly higher in EPA-treated cells (-49.8 +/- 10.4 mV, n = 41) than in control cells (-44.6 +/- 7.4 mV, n = 41, P < 0.05), and the input resistance of the cell was lower in EPA-treated cells, while cell size and capacitance were not statistically different. In addition, long-term treatment with EPA for 7 days significantly inhibited PDGF-induced cell migration. These results suggest that cellular incorporation of n-3 eicosapentaenoic acid attenuates intracellular mechanisms related to changes of [Ca2+]i and affects membrane potential, thereby inhibiting migration of vascular smooth muscle cells. These actions of EPA may contribute to its vasorelaxant and antiatherosclerotic effects.

Animals↗
PubMed1998

Hypoxia and endothelin-1 induce VEGF production in human vascular smooth muscle cells.

Vascular endothelial growth factor/vascular permeability factor (VEGF/VPF) is a secreted mitogen for vascular endothelial cells, and it promotes vascular permeability and neovascularization in vivo. We investigated the mechanisms by which low oxygen tension modulates the expression of VEGF in human aortic vascular smooth muscle cells (h-SMC) in vitro. Moreover, we measured VEGF levels in the cultured medium with or without endothelin-1 (ET-1) using a newly developed, highly sensitive, enzyme-linked immunosorbent assay. Hypoxia resulted in a substantial induction of VEGF transcripts at 3 and 24 hr. VEGF levels were significantly higher when h-SMC were cultured in medium containing ET-1 than when cultured in medium without ET-1. In conclusion, hypoxia and ET-1 constitute potent stimuli for VEGF production in h-SMC.

Cell Hypoxia↗