Biomedical subjects

Osafumi Yuge

Publications and source records attributed to Osafumi Yuge.

At least 19 recordsLinked to original sources

PubMed2006

Intrathecally administered COX-2 but not COX-1 or COX-3 inhibitors attenuate streptozotocin-induced mechanical hyperalgesia in rats.

Members of the cyclooxygenase (COX) family are known to catalyze the rate-limiting steps of prostaglandins synthesis and reported to be involved in neuropathic pain. Diabetic neuropathy is a type of neuropathic pain, though it is not clear if COX is relevant to the condition. Recently, spinal COX-2 protein was found to be increasing in streptozotocin-induced rats as compared to the constitutive expression. We attempted to determine which cyclooxygenase isoforms are involved in streptozotocin-induced mechanical hyperalgesia, which was induced by a single intraperitoneal injection of 75 mg/kg of streptozotocin. Intrathecal administrations of the COX-2 inhibitors SC-58125 (7-100 microg) and NS-398 (7-60 microg), as well as a high dose (100 microg) of the COX-1 inhibitor SC-560 attenuated hyperalgesia, whereas intrathecal administrations of a low dose (10 microg) of SC-560 and the COX-3 inhibitor acetaminophen (1-7 mg) did not. Further, intrathecal administration of SC-58125 (100 microg) did not produce an analgesic effect in normal rats. These results indicate that intrathecal administration of COX-2 inhibitors has an anti-hyperalgesic effect on streptozotocin-induced mechanical hyperalgesia and we concluded that spinal COX-2 is pivotal in streptozotocin-induced hyperalgesia.

Animals↗

PubMed2006

Liver X receptor ligands inhibit the lipopolysaccharide-induced expression of microsomal prostaglandin E synthase-1 and diminish prostaglandin E2 production in murine peritoneal macrophages.

Microsomal prostaglandin E synthase (mPGES)-1, which is dramatically induced in macrophages by inflammatory stimuli such as lipopolysaccharide (LPS), catalyzes the conversion of cyclooxygenase-2 (COX-2) reaction product prostaglandin H(2) (PGH(2)) into prostaglandin E(2) (PGE(2)). The mPGES-1-derived PGE(2) is thought to help regulate inflammatory responses. On the other hand, excess PGE(2) derived from mPGES-1 contributes to the development of inflammatory diseases such as arthritis and inflammatory pain. Here, we examined the effects of liver X receptor (LXR) ligands on LPS-induced mPGES-1 expression in murine peritoneal macrophages. The LXR ligands 22(R)-hydroxycholesterol (22R-HC) and T0901317 reduced LPS-induced expression of mPGES-1 mRNA and mPGES-1 protein as well as that of COX-2 protein. However, LXR ligands did not influence the expression of microsomal PGES-2 (mPGES-2) or cytosolic PGES (cPGES) protein. Consequently, LXR ligands suppressed the production of PGE(2) in macrophages. These results suggest that LXR ligands diminish PGE(2) production by inhibiting the LPS-induced gene expression of the COX-2-mPGES-1 axis in LPS-activated macrophages.

Animals↗

PubMed2006

Synthetic peroxisome proliferator-activated receptor-gamma agonists restore impaired vasorelaxation via ATP-sensitive K+ channels by high glucose.

The present study was designed to examine whether in the human artery, synthetic peroxisome proliferator-activated receptor (PPAR)-gamma agonists restore vasorelaxation as well as hyperpolarization via ATP-sensitive K+ channels impaired by the high concentration of D-glucose and whether the restoration may be mediated by the antioxidant capacity of these agents. The isometric force and membrane potential of human omental arteries without endothelium were recorded. The production rate of superoxide was evaluated using a superoxide-generating system with xanthine-xanthine oxidase in the absence of smooth muscle cells. Glibenclamide abolished vasorelaxation and hyperpolarization in response to levcromakalim. Addition of D-glucose (20 mM) but not L-glucose (20 mM) reduced this vasorelaxation and hyperpolarization. Synthetic PPAR-gamma agonists (troglitazone and rosiglitazone) and/or an inhibitor of superoxide generation (4,5-dihydroxy-1,3-benzene-disulfonic acid, Tiron), but not a PPAR-alpha agonist (fenofibrate), restored vasorelaxation and hyperpolarization in response to levcromakalim in arteries treated with D-glucose. Troglitazone and rosiglitazone, but not fenofibrate, decreased the production rate of superoxide without affecting uric acid generation. These findings suggest that synthetic PPAR-gamma agonists recover the function of ATP-sensitive K+ channels reduced by the high concentration of glucose in human vascular smooth muscle cells and that the effect of these agonists may be mediated in part by their antioxidant capacity.

Adenosine Triphosphate↗

PubMed2006

[Anesthetic management of laser surgery with bronchial stenting for a tracheal tumor].

Anesthetic management during surgery for a tracheal tumor is extremely difficult in terms of airway management. We managed a patient with a tracheal tumor who was successfully treated without complication. The trachea of a 66-year-old woman was narrowed by a tumor to one-third of its original diameter, for which Nd-YAG laser surgery with insertion of an intratracheal Dumon stent was performed. Anesthesia was maintained with neuroleptanalgesia using fentanyl and droperidol, supplemented with a TCI infusion of propofol under spontaneous breathing. High frequency jet ventilation (HFJV) was prepared for intraoperative poor oxygenation and/or ventilation. The patient was able to maintain a good respiratory condition throughout the operation without special respiratory support, including use of HFJV. We conclude that the maintenance of spontaneous breathing is essential for anesthetic management in the present case, while an intraoperative airway strategy based on the preoperative breathing condition of the patient is also important.

Aged↗

PubMed2006

[Validity of intraoperative administration of dexmedetomidine in a patient with dermatomyositis-derived respiratory failure].

A 66-year-old female with dermatomyositis and severe respiratory failure from collagen lungs, dependent on domiciliary oxygen therapy, was scheduled for a mastectomy. Anesthesia was induced with dexmedetomidine (DEX) 6 microg x kg(-1) x h(-1) for 10 minutes and maintained at 0.7 microg x kg(-1) x h(-1), along with a target controlled infusion of propofol combined with epidural anesthesia. No narcotic or muscle relaxant was used. The airway was secured using a laryngeal mask airway and spontaneous breathing was preserved. The perioperative course was uneventful without any pulmonary complications. DEX has a certain analgesic property and a mild respiratory depressant effect. Therefore, it is considered useful as a concomitant anesthetic agent for perioperative management of patients with respiratory failure.

Aged↗

PubMed2006

[Evaluation of the sedation level with propofol with electroencephalographic Entropy in comparison with bispectral index monitor].

BACKGROUND: Entropy, a newly available electroencephalographic monitor, demonstrates two parameters, response entropy (RE) and state entropy (SE). The aim of this study is to compare RE and SE with bispectral index (BIS) during anesthetic induction with propofol. METHODS: Fifteen patients received target controlled infusion of propofol starting at 3 microg x ml(-1). We measured RE, SE and BIS and recorded effect-site concentrations of propofol at three sedation levels: VR1; conscious state before infusion of propofol, VR2; no response to verbal command, and VR3; no response to verbal command and shaking. Spearman rank correlations and prediction probability for sedation level were analyzed. RESULTS: Effect-site concentrations of propofol at VR1, VR2, and VR3 were 0, 1.8 +/- 0.7, and 2.4 +/- 0.7, respectively. All three parameters showed significant correlations with sedation levels. Prediction probability values of SE, RE, and BIS were 0.905, 0.894, and 0.890, respectively. CONCLUSIONS: Response entropy and SE can provide similar information as BIS about the sedation level with propofol.

Adult↗

PubMed2005

Suppression of inducible nitric oxide synthase and cyclooxygenase-2 gene expression by 22(R)-hydroxycholesterol requires de novo protein synthesis in activated macrophages.

Liver X receptors (LXRs) play an important role in lipid metabolism. Recently, a role for these proteins was identified in suppressing the inflammatory response. However, it is not known whether the natural ligands of LXRs, e.g. 22(R)-hydroxycholesterol (22R-HC), can suppress the inflammatory response after the onset of inflammation. We demonstrate here that treatment of Lipopolysaccharide (LPS)-activated RAW264.7 macrophages with 22R-HC markedly suppressed nitric oxide (NO) production and inducible NO synthase (iNOS) and cyclooxygenase-2 (COX-2) mRNA expression. Additionally, 22R-HC did not affect the DNA binding activity of NF-kappaB, AP-1 and C/EBP(s), important transcriptional factors for iNOS and COX-2 genes expression. Furthermore iNOS and COX-2 mRNA suppression by 22R-HC was diminished by cellular treatment with cycloheximide. These results suggest that 22R-HC suppresses the expression of iNOS and COX-2 genes through de novo protein synthesis of an unidentified protein in LPS-activated macrophages.

Animals↗

PubMed2005

Spinal orexin-1 receptors mediate anti-hyperalgesic effects of intrathecally-administered orexins in diabetic neuropathic pain model rats.

Orexin-A and orexin-B are endogenous ligands of orexin receptors that contain orexin-1 and orexin-2. Activation of the orexinergic system can produce antinociceptive effects in acute inflammatory, mono-neuropathic, and postoperative pain animal models, though the effects of orexins on diabetic neuropathic pain have not been previously investigated. In this study, we studied the anti-hyperalgesic effects of intrathecally administered orexins in a streptozotocin-induced diabetic rat. First, dose-dependent effects were investigated by measuring hind paw withdrawal thresholds in response to noxious-heat and punctate stimuli, after which orexin levels in the cerebrospinal fluid of diabetic rats were measured and compared with those of normal rats using a radioimmunoassay method. The functional role of spinal orexin-1 receptors with the anti-hyperalgesic effects of orexins was also investigated using intrathecal pretreatment with SB-334867, a selective orexin-1 receptor antagonist. Intrathecally administered orexins produced an antinociceptive effect in diabetic rats, however, not in normal rats, though the orexin levels in the cerebrospinal fluid of diabetic rats were similar to those in normal rats. In addition, the anti-hyperalgesic effects of orexins were significantly inhibited by pretreatment with SB-334867. These findings demonstrate that the anti-hyperalgesic effects of orexins in diabetic rats are unlikely due to any direct effect by the supplement on decreased endogenous orexins in the cerebrospinal fluid and that orexin-1 receptors in the spinal cord may be involved in the modulation of nociceptive transmission in diabetic neuropathy. We conclude that the spinal orexinergic system may be a possible target for elucidating the mechanisms of diabetes-induced hyperalgesia.

Animals↗

PubMed2005

CB(1) cannabinoid receptor stimulation modulates transient receptor potential vanilloid receptor 1 activities in calcium influx and substance P Release in cultured rat dorsal root ganglion cells.

Cannabinoids have been reported to have analgesic properties in animals of acute nociception or of inflammatory and neuropathic pain models, but the mechanisms by which they exert such alleviative effects are not yet fully understood. We investigated whether the CB(1)-cannabinoid-receptor agonist HU210 modulates the capsaicin-induced (45)Ca(2+) influx and substance P like-immunoreactivity (SPLI) release in cultured rat dorsal root ganglion (DRG) cells. HU210 attenuated the capsaicin-induced (45)Ca(2+) influx and this effect was reversed by the CB(1) antagonist AM251. Treatment of DRG cells with 100 nM bradykinin for 3 h potentiated capsaicin-induced SPLI release accompanied with the induction of cyclooxygenase-2 mRNA expression. The potentiation of SPLI release by bradykinin was reversed by HU210 or the protein kinase A (PKA) inhibitor H-89. HU210 also reduced forskolin-induced cyclic AMP production and forskolin-induced potentiation of SPLI release. These results suggest that CB(1) could inhibit either the capsaicin-induced Ca(2+) influx or the potentiation of capsaicin-induced SPLI release by a long-term treatment with bradykinin through involvement of a cyclic-AMP-dependent PKA pathway. In conclusion, CB(1)-receptor stimulation modulates the activities of transient receptor potential vanilloid receptor 1 in cultured rat DRG cells.

Animals↗

PubMed2005

Undisrupted pulse wave on pulse oximeter display monitor at cardiac arrest in a surgical patient.

We have encountered a case of cardiac arrest during anesthesia care in which an application of a new-generation pulse oximetry technology led to a misleading interpretation of the patient's true condition. Just after manipulation of the peritoneum, the heart rhythm suddenly became asystole, while the ECG showed a standstill and an arterial pressure wave was absent. However, the Datex-Ohmeda AS/3 Patient Monitor connected to the Masimo SatShare Waveform Generator feature continued to display a pulse wave with a reading of 99%. Because we assumed the reading to be reliable, we took no immediate action. However, the ECG standstill and flattened arterial wave lasted for about 10 s, with no pulse at the common carotid artery; thus, 0.5 mg atropine and 4 mg ephedrine were given and chest compression performed using ventilation with oxygen. About 20 s later, the heart rhythm reappeared, which was monitored by the ECG and arterial pulse wave. This incident demonstrates the importance of becoming familiar with a new technology; otherwise, we will fall into medical errors.

Adult↗

PubMed2005

Comparison of the effects of propofol and midazolam on the cardiovascular autonomic nervous system during combined spinal and epidural anesthesia.

STUDY OBJECTIVE: To investigate the effect of propofol and midazolam on cardiac autonomic nervous system (CANS) activity during combined spinal-epidural anesthesia. DESIGN: Prospective, clinical study. SETTING: Operating room of a university hospital. PATIENTS: Forty ASA physical status I and II patients scheduled for knee surgery. INTERVENTION: Patients were randomized to receive sedation with either propofol or midazolam. MEASUREMENTS: Heart rate (HR), HR variability (HRV), systolic arterial pressure (SAP), and SAP variability (SAPV) were used for the analysis. These values were measured at the preanesthetic period, after intrathecal injection for spinal anesthesia, after sedation with propofol or midazolam, and just before the end of surgery with sedation. Cross-spectral analyses of the HR and SAP data were assessed to quantify the frequency-related coherence spectra and phase spectra. MAIN RESULTS: Spinal anesthesia itself had no effect on power spectral changes in both groups. After sedation, as for HRV, high-frequency (HF) power (HF, 0.15-0.40 Hz) did not change, whereas low-frequency (LF) power (LF, 0.04-0.15 Hz) and LF/HF, an indicator of CANS balance, significantly decreased with propofol. Further, coherence in cross-spectra presented depression in the LF band area after sedation with propofol. Before the end of surgery with sedation, LF and LF/HF in both HRV and SAPV were correlated with age in those with propofol; however, scarce relation was observed in those who received midazolam. CONCLUSIONS: Propofol was more potent than midazolam in causing CANS activity to be sympatholytic during combined spinal and epidural anesthesia and which was correlated with age only with propofol.

Adult↗

PubMed2005

General anesthesia for patient with type III homocystinuria (tetrahydrofolate reductase deficiency).

Homocystinuria, a rare autosomal recessive genetic disease, is generally classified into 3 types (types I-III). Extremely rare type III is from a defect of the enzyme tetrahydrofolate reductase which converts homocysteine to methionine. The anesthetic problem of type III homocystinuria is the elevation of serum homocysteine and the deficiency of essential amino acid methionine, which result in the perioperative thromboembolic events and nitrous oxide-induced neurological impairment. We provided successful anesthetic management for a patient with type III homocystinuria, during which we were careful to take measures against perioperative thromboembolism and did not use nitrous oxide.

Adult↗

PubMed2005

[Perioperative use of recombinant activated factor VII (rF VIIa) in a patient with hemophilia A having inhibitors].

We experienced the perioperative management of a patient with hemophilia A having inhibitors using recombinant activated factor VII (rF VIIa). A 55-year-old man was scheduled for right total hip arthroplasty. Since he developed high titer of VIII inhibitor, rF VIIa was utilized for the hemostatic control for "bypass therapy". Dosage and interval for perioperative rF VIIa administration were determined before the surgery with a trial injection. Just before anesthesia induction, rF VIIa (9.6 mg) was given and repeated every 2 hrs during surgery till the 2nd post operative day (POD). Thereafter, rF VIIa was repeatedly given in decremental steps till 5th POD. Although intraoperative bleeding was 2500 g and 1200 ml of RBC was transfused, post surgical bleeding was minimal and no adverse effect was observed. He was discharged on 46th POD without any trouble. Perioperative rF VIIa administration is safe and useful for hemostatic control in a patient with hemophilia A having inhibitor.

Arthroplasty, Replacement, Hip↗

PubMed2004

Inhibitory effect of high concentration of glucose on relaxations to activation of ATP-sensitive K+ channels in human omental artery.

OBJECTIVE: The present study was designed to examine in the human omental artery whether high concentrations of D-glucose inhibit the activity of ATP-sensitive K+ channels in the vascular smooth muscle and whether this inhibitory effect is mediated by the production of superoxide. METHODS AND RESULTS: Human omental arteries without endothelium were suspended for isometric force recording. Changes in membrane potentials were recorded and production of superoxide was evaluated. Glibenclamide abolished vasorelaxation and hyperpolarization in response to levcromakalim. D-glucose (10 to 20 mmol/L) but not l-glucose (20 mmol/L) reduced these vasorelaxation and hyperpolarization. Tiron and diphenyleneiodonium, but not catalase, restored vasorelaxation and hyperpolarization in response to levcromakalim in arteries treated with D-glucose. Calphostin C and Gö6976 simultaneously recovered these vasorelaxation and hyperpolarization in arteries treated with D-glucose. Phorbol 12-myristate 13 acetate (PMA) inhibited the vasorelaxation and hyperpolarization, which are recovered by calphostin C as well as Gö6976. D-glucose and PMA, but not l-glucose, significantly increased superoxide production from the arteries, whereas such increased production was reversed by Tiron. CONCLUSIONS: These results suggest that in the human visceral artery, acute hyperglycemia modulates vasodilation mediated by ATP-sensitive K+ channels via the production of superoxide possibly mediated by the activation of protein kinase C.

Adenosine Triphosphate↗

PubMed2004

Effect of etodolac, a COX-2 inhibitor, on neuropathic pain in a rat model.

Etodolac, a cyclooxygenase-2 inhibitor, may alleviate nociceptive pain and inhibit the activation of osteoclasts. The aim of the present study was to determine whether etodolac can alleviate heat-evoked hyperalgesia and investigate its possible protective effects on osteoporosis induced by chronic constriction injury (CCI) in rats. A CCI to the sciatic nerve was performed, after which the rats received etodolac orally in a volume of 2 ml at 0, 1, and 10 mg/kg/day for 1 to 5 weeks following surgery (experiment 1); at 0 and 10 mg/kg/day for 1 day to 5 weeks following surgery (experiment 2); and at 0 mg/kg/day for 1 to 5 weeks, 10 mg/kg/day for 1 to 2 weeks after surgery, or 10 mg/kg/day for 1 to 3 weeks after surgery (experiment 3). Paw withdrawal latency after exposure to heat, bone mineral content (BMC) and bone mineral density (BMD) in the whole tibial bone, and the number of tartrate resistant acid phosphate (TRAP)-positive multinucleated osteoclasts were measured. Etodolac alleviated heat-evoked hyperalgesia in the CCI rats and the increase in number of TRAP-positive multinucleated osteoclasts on the CCI-side was abrogated, however, it did not inhibit the decrease of BMC and BMD on the CCI-side. Our results suggest that etodolac is useful for treatment of neuropathic pain.

Acid Phosphatase↗

PubMed2004

[Comparison of emergency tracheal intubation performed on a table and on the ground].

BACKGROUND: Emergency tracheal intubation in the pre-hospital environment is generally more difficult than when performed at a hospital. Among the reasons making it more challenging, is the rescuer's position. We compared tracheal intubation between 2 settings, on a table and on the ground. METHODS: Ten staff anesthesiologists were asked to intubate mannequins placed on a table and on the ground. Measured variables included intubation time, Cormack grade, incidence of esophageal intubation, "crick" sound from the teeth of the mannequin, and degree of head tilt during intubation attempts. RESULTS: Mean intubation times on the table and ground were 12.6 +/- 3.9 and 14.7 +/- 6.5 seconds, respectively. No esophageal intubation occurred. Cormack grades and incidence of teeth click were significantly higher on the floor, whereas there was no difference regarding degree of head tilt between the 2 settings. CONCLUSIONS: Our results indicate that intubation on the ground is more difficult and may require a longer time to accomplish, even for experienced anesthesiologists. Therefore, those involved in airway management training for emergency personnel should acquire appropriate skills to teach tracheal intubation in such a difficult situation.

Anesthesiology↗

PubMed2004

[Low oxygen saturation during early postoperative period in adult patients receiving opioids by intravenous patient-controlled analgesia].

BACKGROUND: Patient-controlled analgesia (PCA) provides effective postoperative analgesia. However, there are few reports concerning the adverse outcome of respiratory depression. METHODS: We measured arterial oxygen saturation (SpO2) continuously during early postoperative period in 38 adult patients receiving opioids by intravenous PCA. We assessed the severity and incidence of desaturation, defined as SpO2 below 90% for more than 10 seconds. RESULTS: Nine patients showed desaturation and were studied after the surgery of the extremities, body surfaces, thorax or abdomen. Two patients showed desaturation with combination of surgery of long duration and obesity. Six patients, all of whom with liver cirrhosis, underwent thoracic and abdominal procedures, and showed desaturation because of respiratory dysfunction and hypoxemia caused by the surgery itself. One patient showed respiratory depression due to the opioids. CONCLUSIONS: We conclude that careful monitoring with a pulse oximeter and giving oxygen are essential to prevent desaturation during early postoperative period.

Adult↗

PubMed2004

[Preoperative prediction of creatinine clearance by using serum creatinine].

BACKGROUND: Creatinine clearance (Ccr) is an efficient index of renal function. However, measurement of Ccr is not routinely performed for preoperative patients. To predict preoperative renal impairment, we estimated the preoperative Ccr by using serum creatinine (sCr) and other laboratory findings. METHODS: 702 patients served as the training samples and other 128 patients as the validation samples. (1) Values of sCr and BUN to predict lower Ccr levels were developed from the training samples. In the combination of sCr and BUN, we selected the optimal combination in receiver operating characteristics curve. This value was applied to the validation samples. (2) The predictive equation was derived from the training samples by multiple regression analysis, and it was compared with the equations previously reported. RESULTS: (1) The optimal sensitivity and specificity for predicting Ccr less than 30 ml x min(-1) x 1.48 m(-2) were 60% and 84%, respectively. (2) Among the equations to predict Ccr, our equation showed the highest correlation coefficient (r), and the smallest differences between predicted and measured Ccr. CONCLUSIONS: We determined the values of sCr and BUN to predict renal impairment and derived predictive equation. Our equation was the best to assess the preoperative renal function.

Blood Urea Nitrogen↗