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Biomedical subjects

Y Okuda

Publications and source records attributed to Y Okuda.

At least 73 records · Page 4Linked to original sources
PubMed2000

Propofol prevents lipid peroxidation following transient forebrain ischemia in gerbils.

PURPOSE: To ascertain whether propofol prevents lipid peroxidation on delayed neuronal death induced by transient forebrain ischemia in the hippocampal CA1 subfield in gerbils. METHODS: Forty gerbils were randomly assigned to five groups: Group I, control, sham operation treated with physiological saline solution (PSS); Group II, ischemia/reperfusion treated with PSS; Group III, ischemia/reperfusion treated with 50 mg x kg(-1) propofol; Group IV, ischemia/reperfusion treated with 100 mg x kg(-1) propofol; Group V, ischemia/reperfusion treated with 150 mg x kg(-1) propofol. Transient forebrain ischemia was induced by occluding the bilateral common carotid arteries for four minutes under N2O/O2/halothane anesthesia after propofol or PSS. Five days later, the cerebrum was removed and each forebrain was cut into two including the hippocampus. Lipid peroxidation was determined using the production of malondialdehyde (MDA), and histopathological changes in the hippocampal CA1 subfield were examined. RESULTS: In group II, the pyramidal cells were atrophic and pycnotic; vacuolation and structural disruption of the radial striated zone was observed. In the other four groups, these changes were not observed. Degenerative ratios of pyramidal cells were: Group I: 4.9 +/- 2.3, Group II: 94.1 +/- 4.5 (P < 0.01), Group III: 12.5 +/- 5.7, Group IV: 11.0 +/- 4.6, Group V: 9.6 +/- 4.9%. Production of MDA was: Group I: 83 +/- 22, Group II: 198 +/- 25 (P < 0.01), Group III: 153 +/- 39, Group IV: 113 +/- 34, Group V: 106 +/- 27 nmol x g(-1) wet tissue. CONCLUSION: Propofol attenuated delayed neuronal death by preventing lipid peroxidation induced by transient forebrain ischemia in the hippocampal CA1 subfield in gerbils.

Animals↗
PubMed2000

Proton magnetic resonance spectroscopy of a patient with Gerstmann-Straussler-Scheinker disease.

A 23-year-old woman with Gerstmann-Straussler-Scheinker disease (GSS) was investigated by 1H-magnetic resonance spectroscopy (1H-MRS). She developed gait ataxic at 22 years. The diagnosis was confirmed by DNA analysis showing a proline-to-leucine point mutation at codon 102 of the prion protein. On 1H-MRS, she showed a remarkable reduction of the N-acetylaspartate/creatine ratio in the frontal lobe, cerebellar hemisphere and vermis and putamen. MRI revealed mild atrophy of the cerebellar hemispheres and vermis and cerebral cortex, but single-photon emission computed tomography (SPECT) with 99mHMPAO showed normal perfusion in the cerebellum. The imaging studies suggest that MRS might be superior to MRI or SPECT for detection of early neuronal degeneration.

Adult↗
PubMed2000

A comparison between low-flow leak test and oxygen flush leak test.

PURPOSE: The clinical efficacy of two methods of preanesthetic leak test,namely the oxygen flush leak test (OFLT) and the low-flow leak test (LFLT), was compared regarding their ability to detect leakage in the anesthesia circuit and their accuracy. METHODS: Examinees comprised 16 staff anesthesiologists and 7 physicians undergoing anesthesia training at our institution. They performed the two leak tests on anesthesia machines with some intentional leaks (0.1-1.0 l.min(-1)). The leakage detection rates (LDR) were analyzed by the chi(2)-test. The ability to detect leaks was measured by recording how many leaks were detected by 50% (LDR(50)) and 95% (LDR(95)) of the examinees. RESULTS: The LDRs in the two tests were significantly different (chi(2)- analysis, P < 0.0001). Both LDR(50) and LDR(95) for the LFLT (0.23 and 0.41 l.min(-1), respectively) were smaller than the values for the OFLT (0.37 and 0.82 l.min(-1), respectively). The sensitivity and specificity of the LFLT (0.97 and 0.84, respectively) were higher than those of the OFLT (0.78 and 0.80, respectively). CONCLUSION: The LFLT was found to be superior to the OFLT regarding leak detection and reliability. We therefore recommend the LFLT for preanesthetic leak testing.

Journal Article↗
PubMed2000

Enhanced graft healing of high-porosity expanded polytetrafluoroethylene grafts by covalent bonding of fibronectin.

The effect of covalent bonding of fibronectin on the patency and graft healing of high-porosity expanded polytetrafluoroethylene (ePTFE) grafts was evaluated. Bilateral carotid grafting was performed in ten mongrel dogs using high-porosity (60 microm) ePTFE grafts, 4 cm in length and 4 mm in internal diameter, that either had been pretreated by the covalent bonding of fibronectin (fibronectin grafts) or were untreated (control grafts). The grafts were harvested 4 to 6 weeks after surgery and subjected to macroscopic and light-microscopic observations. There was no significant difference in patency between the fibronectin grafts and the control grafts with rates of 80% and 70%, respectively. The thrombus-free area score was significantly greater in the fibronectin grafts than in the control grafts, at 86.9% vs 34.0%. Furthermore, the pseudointima was better replaced by fibrous tissue in the fibronectin grafts than in the control grafts, being lined with a layer of endothelial-like cells. More transmural tissue ingrowth was evident in the fibronectin grafts than in the control grafts. The covalent bonding of fibronectin improves graft healing by stimulating transmural tissue ingrowth in high-porosity ePTFE grafts.

Animals↗
PubMed2000

High-porosity expanded polytetrafluoroethylene grafts for thoracic vena cava replacement with or without an omentum wrap.

We previously reported that, in a short-term thoracic inferior vena cava (IVC) replacement, a high-porosity expanded polytetrafluoroethylene (ePTFE) graft (fibril length 60 microm) performed well without altering the short-term patency, and that the healing of the high-porosity ePTFE graft was accelerated by an omentum wrap. The purpose of this study was to examine the long-term performance of the high-porosity ePTFE graft with or without an omentum wrap. Eighteen grafts were placed as a thoracic IVC replacement in dogs. Nine of the grafts were wrapped in an omental pedicle flap while the other 9 were not. At 1 month and 6 months, the grafts were harvested and examined for a pathological analysis. During the observation period, one dog died of a viral infection, while the other 17 dogs survived. At 1 month and 6 months, the patency rates of the 17 grafts were 100% regardless of the presence or absence of an omentum wrap. The healing of the grafts without omentum wrap was incomplete 6 months after implantation; granulation tissue was present in the center of the pseudointima. The grafts healed completely by the addition of an omentum wrap. Our data suggest that, with an omentum wrap, the high-porosity ePTFE graft is fully expected to show a good long-term function.

Animals↗
PubMed2000

Delapril versus manidipine in hypertensive therapy to halt the type-2-diabetes-mellitus-associated nephropathy.

Thirty-nine hypertensive patients with type 2 diabetes mellitus were followed under long-term treatment (mean, 20.7 months) with manidipine hydrochloride, a Ca antagonist, or delapril hydrochloride, an ACE inhibitor, at nine institutions. Both the treatments showed similar antihypertensive effects, although slight but significantly larger decreases were observed in systolic and mean blood pressures at months 12 and 24 in the patients treated with manidipine (P < 0.02). The urinary albumin excretion index (AEI) tended to increase throughout the study in both treatment groups, but no significant difference in AEI was observed between the two treatment groups at any time point. Overt albuminuria developed in four patients on manidipine but did not appear in any of the patients on delapril. The risk of progression to overt albuminuria was significantly different between manidipine and delapril groups (P = 0.011). No increase in serum creatinine (Cr) was observed with delapril. The average excretion indexes of tubular markers such as beta2-microglobulin, alpha1-microglobulin, and NAG tended to be higher in the patients on manidipine than in those on delapril. Taken in sum, these findings suggest that the ACE inhibitor delapril is more beneficial than the Ca antagonist manidipine in the treatment of diabetic renal diseases via mechanisms other than the blood pressure regulation, partly through their different effects on tubular function. In conclusion, delapril was significantly more effective than manidipine in inhibiting progression to overt albuminuria in hypertensive type 2 diabetes mellitus patients.

Adult↗
PubMed2000

Bile acids increase intracellular Ca(2+) concentration and nitric oxide production in vascular endothelial cells.

The effects of bile acids on intracellular Ca(2+) concentration [Ca(2+)](i) and nitric oxide production were investigated in vascular endothelial cells. Whole-cell patch clamp techniques and fluorescence measurements of [Ca(2+)](i) were applied in vascular endothelial cells obtained from human umbilical and calf aortic endothelial cells. Nitric oxide released was determined by measuring the concentration of NO(2)(-). Deoxycholic acid, chenodeoxycholic acid and the taurine conjugates increased [Ca(2+)](i) concentration-dependently, while cholic acid showed no significant effect. These effects resulted from the first mobilization of Ca(2+) from an inositol 1,4,5-triphosphate (IP(3))-sensitive store, which was released by ATP, then followed by Ca(2+) influx. Both bile acids and ATP induced the activation of Ca(2+)-dependent K(+) current. Oscillations of [Ca(2+)](i) were occasionally monitored with the Ca(2+)-dependent K(+) current in voltage-clamped cells and Ca(2+) measurements of single cells. The intracellular perfusion of heparin completely abolished the ATP effect, but failed to inhibit the bile acid effect. Deoxycholic acid and chenodeoxycholic acid enhanced NO(2)(-) production concentration-dependently, while cholic acid did not enhance it. The bile acids-induced nitric oxide production was suppressed by N(G)-nitro-L-arginine methyl ester, exclusion of extracellular Ca(2+) or N-(6-aminohexyl)-5-chloro-l-naphthalenesulphonamide hydrochloride (W-7) and calmidazolium, calmodulin inhibitors. These results provide novel evidence showing that bile acids increase [Ca(2+)](i) and subsequently nitric oxide production in vascular endothelial cells. The nitric oxide production induced by bile acids may be involved in the pathogenesis of circulatory abnormalities in liver diseases including cirrhosis.

Animals↗
PubMed2000

Cremasteric reflex test as an objective indicator of spinal anaesthesia.

We studied 100 men who were scheduled for urological surgery (Group 1) and another 50 men for orthopaedic surgery (Group 2). We attempted to anaesthetise both sides of the lower body in Group 1 and to anaesthetise one leg in Group 2 by injecting 0.3% hyperbaric dibucaine intrathecally. The presence or absence of the cremasteric reflex and loss of sensation to pinprick higher than the first lumbar dermatome were examined by two researchers who were blind to each other's results. In Group 1, both the reflex and the pinprick sensation were always absent bilaterally 5 min after intrathecal injection. In Group 2, in 23 of 50 patients the reflex had become absent bilaterally; in all these patients, bilateral sensory loss was detected. In the remaining 27 patients, both the reflex and the pinprick sensation were absent on the operation side, whereas both were present on the nonoperation side. Sensitivity, specificity and positive or negative predictive value for the cremasteric reflex were all 100%. Disappearance of the cremasteric reflex is a simple objective indicator of spinal anaesthesia at the first lumbar dermatome. This test may be useful in patients who cannot give reliable answers to conventional tests, such as the pinprick test.

Adult↗
PubMed2000

Airway obstruction during general anaesthesia in a child with congenital tracheomalacia.

Fibreoptic bronchoscopy is often used to diagnose tracheomalacia under local anaesthesia. However, in children, general anaesthesia may be required due to difficulty in obtaining co-operation. A 1-yr-old girl with a suspected congenital tracheomalacia was scheduled for diagnostic fibreoptic bronchoscopy. During induction of anaesthesia by inhalation of increasing concentration of sevoflurane, spontaneous breathing became irregular and a partial airway obstruction occurred. Because vecuronium relieved the airway obstruction, the airway was managed using a laryngeal mask. No further airway obstruction occurred during fibrescopy under controlled ventilation, but when spontaneous breathing resumed, marked airway obstruction occurred. The trachea was intubated immediately. Caution is required to manage the airway without tracheal intubation during general anaesthesia in the patient with tracheomalacia.

Airway Obstruction↗
PubMed2000

Expression of cyclooxygenase-2 and nitrotyrosine in human gastric mucosa before and after Helicobacter pylori eradication.

To determine whether cure of Helicobacter pylori infection influences the expression of COX-2 and nitrotyrosine in the distal stomach of humans, biopsy specimens were examined immunohistochemically. H. pylori infection was determined using a rapid urease test, culture and histology. Positive staining of COX-2/nitrotyrosine in the epithelium was expressed as the percentage of stained cells to the total epithelial cells. There was a significant increase in COX-2/nitrotyrosine staining in H. pylori -positive subjects compared with H. pylori -negative subjects. Cure of the infection resulted in a significant decrease in both COX-2/nitrotyrosine staining in all patients (52.1+/-12.1% vs 15. 4+/-7.2%, P<0.001; and 57.3+/-13.6% vs 36.1+/-18.0%, P<0.01, respectively). However, immunoreactivity of COX-2/nitrotyrosine was observed in all cases with intestinal metaplasia even after the cure of H. pylori infection.Thus, cure of H. pylori infection may decrease the risk of gastric carcinogenesis due to COX-2 and NO-related compounds in gastric mucosa but not in those patients with intestinal metaplasia.

Adult↗
PubMed2000

Symptomatic improvement in dyspnea following tracheobronchial metallic stenting for malignant airway obstruction.

PURPOSE: To investigate the value and limitation of Gianturco expandable metallic stenting for patients with dyspnea due to stenotic tracheobronchial lesions associated with malignancies. MATERIAL AND METHODS: We treated 55 lesions of 44 patients with obstructing stenotic tracheobronchial lesions related to end-stage malignancies by Gianturco expandable metallic stents (EMSs). RESULTS: In 42 of 44 patients, the dyspnea subjectively improved after the procedure (95.5%). An improvement over one grade of the Hugh-Jones classification was shown in 79.5% (35/44); in 80% (20 of 25 patients) with intraluminal tumor and in 78.9% (15 of 19 patients) with extrinsic compression. Seven of the 44 patients developed dyspnea related to re-stenosis of 10 lesions and 1 of these patients developed dyspnea related to re-re-stenosis during follow-up. The mean duration of survival was 4.3 months in patients who underwent stenting. No significant differences in survival rates and primary patency rates were seen in patients with extrinsic compression compared to patients with intraluminal tumors. CONCLUSION: Gianturco EMS therapy was valuable in patients who suffered from dyspnea due to airway stenosis causing obstruction.

Adult↗
PubMed2000

Inhibition of apoptosis in cultured immature rat Leydig cells by human chorionic gonadotropin associated with Bcl-2 mRNA expression.

Bcl-2 is the first identified negative regulator of apoptotic cell death. When the level of Bcl-2 mRNA in rat whole testes was examined in the present study, it gradually decreased in rats from 2.5 to 9 weeks old. We also examined the effect of human chorionic gonadotropin (hCG) on apoptosis and the level of Bcl-2 mRNA expression in immature Leydig cells in vitro. When the cells were cultured with serum free media (SFM), Bcl-2 mRNA levels gradually decreased. On the other hand, the level of Bcl-2 mRNA in cells treated with 50 ng/ml of hCG decreased at 6 h, but increased after 12 h. At 24 h, the level of Bcl-2 mRNA in the treated cells was almost the same as that of control cells (time = 0). At 12 h after the addition of various concentrations (from 0.1-1000 ng/ml) of hCG, Bcl-2 mRNA levels increased in a dose-dependent manner. An analysis of DNA fragmentation showed that treatment with hCG prevents the apoptosis of immature Leydig cells. Our findings suggest that Bcl-2 mRNA may be related to the programmed cell death of immature rat Leydig cells in vitro, which are inhibited by hCG.

Animals↗
PubMed2000

Structure, expression, and conserved physical linkage of mouse testicular cell adhesion molecule-1 (TCAM-1) gene.

Isolation and characterization were performed for cDNA encoding mouse testicular cell adhesion molecule-1 (TCAM-1) using 2908 bases coding for a protein having 548 amino acids (60 kDa). Mouse TCAM-1 protein was found to consist of seven domains for signal sequence, five immunoglobulin (Ig) domains, and the transmembrane plus cytoplasmic domain. TCAM-1 gene and the region linking it to growth hormone (GH) gene located downstream from the TCAM-1 gene were then analyzed. The mouse TCAM-1 gene was 11.6 kb in length with 8 exons; the same as for the 12.0 kb rat gene. The distance from the TCAM-1 to GH gene was 12.5 kb in the mouse genome, and 7.6 kb in the rat. By Northern hybridization, 3.1-kb TCAM-1 mRNA was detected in 17-day testis and would appear present in pachytene spermatocytes and round spermatids.

Amino Acid Sequence↗
PubMed2000

Creation of aortic dissection model in swine.

The use of mongrel dogs for experimental purposes was recently restricted and this report presents the experience of creating an aortic dissection model in swine. All the swine in group 1 were anesthetized without pentobarbital and the descending aorta was side-clamped during the creation of the aortic dissection. The false lumen of the completed dissection was patent in the long term despite not having the anchoring suture that the previous canine model required to stabilize the opening of the entry tear. All the swine anesthetized with pentobarbital (ie, group 2) died of heart failure either during cross-clamping of the descending aorta or postoperative aortography. In conclusion, creation of a thoracic aortic dissection is possible in swine, but cross-clamping of the thoracic descending aorta and pentobarbital anesthesia should be avoided.

Aortic Dissection↗
PubMed2000

[Anesthetic management of a patient with West syndrome].

A 21-year-old female with West syndrome was scheduled for resection of hordeolum. She had an episode of convulsion at three months of age, and was diagnosed as having West syndrome at one year of age. She had epileptic seizures twice a week in spite of administration of phenytoin, clonazepam and sodium valproate. These drugs had been administered till the morning of the surgery. After premedication with atropine 0.25 mg, anesthesia was induced with propofol (12-->10-->8 mg.kg-1.h-1). The tracheal intubation was performed with vecuronium 0.1 mg.kg-1 and anesthesia was maintained with continuous infusion of propofol 6-8 mg.kg-1.h-1 and local infiltration with 1.0% lidocaine 5 ml. We administered phenytoin to prevent epileptic seizures during the surgery. No epileptic seizures occurred perioperatively. We conclude that propofol may be useful for a patient with West syndrome, and we should be careful not to lower the threshold for convulsion during the perioperative period.

Adult↗
PubMed2000

[Anesthetic management of bilateral lung lavage for pulmonary alveolar proteinosis--comparison between sevoflurane and propofol].

A 55-year-old man with pulmonary alveolar proteinosis underwent lung lavage under general anesthesia using sevoflurane three years ago. Although transient hypoxia occurred postoperatively, there were no complications. Because of the recent deterioration of his symptoms, he was rescheduled for lung lavage. Anesthesia was induced with propofol 120 mg and fetanyl 0.2 mg. Vecuronium 7 mg was administered to facilitate tracheal intubation using a double-lumen tube. Anesthesia was maintained with propofol 4 mg.kg-1.h-1. Electrocardiogram, blood pressure, SPO2, EtCO2 and rectal temperature were monitored intraoperatively. We also checked PaO2 when necessary. Although transient hypoxia occurred after the procedure, it receded spontaneously. Since inhalation anesthetics inhibit hypoxic pulmonary vasoconstriction, intravenous anesthetics may be more useful for patients with severe pulmonary alveolar proteinosis.

Anesthesia, General↗