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Biomedical subjects

O Yuge

Publications and source records attributed to O Yuge.

At least 19 recordsLinked to original sources
PubMed1998

Parasympathetic activity in brain death: effect of apnea on heart rate variability.

BACKGROUND: Power spectral analysis of heart rate variability is a useful monitoring of brain-damaged patients. However, the effect of artificial ventilation is not clearly demonstrated in assessing vagal activity because the locus of its activity is originated close to the respiratory center in the brain stem. We studied heart rate variability during artificial ventilation and apnea test as part of an assessment of brain death. METHODS: Ten adult patients with severe brain damage were studied. Power spectral analysis of heart rate variability from electrocardiographic R-R intervals was integrated to compare spectral components before, during and after the apnea test. Before the test, circulatory and blood gas variables and electrocardiographic recording were obtained under controlled mechanical ventilation at a rate of 12 and 18 (/min), each for 5 min. Measurements were made for 10 min during the apnea test, and repeated thereafter as before the test. Power spectral analysis based on fast Fourier transformation was made by integrating each low- (LF: 0.04-0.15 Hz) and high- (HF: 0.15-0.40 Hz) frequency band areas. LF was assessed as sympathetic and parasympathetic nervous activity, and HF as respiratory-related parasympathetic vagal activity. The HF/LF ratio showed sympathovagal balance. RESULTS: All patients were assessed as brain dead. During apnea, PaCO2 (P<0.01) and LF (P<0.05) increased, and pH (P<0.01) and HF/LF ratio (P<0.05) decreased. Heart rate, mean arterial pressure, PaO2 and HF remained consistent throughout. CONCLUSION: It was shown that sympathovagal balance was inclined to be sympathotonic during apnea, and that there were no changes in the respiratory-related vagal activity in spite of stopping artificial ventilation.

Adolescent↗
PubMed1998

Living related partial liver transplantation for primary biliary cirrhosis--a case report.

An adult living related partial liver transplantation was performed on a 49 year old female with terminal hepatic failure due to primary biliary cirrhosis (PBC). The donor was her 53 year-old sister. A sufficient volume of graft tissue was obtained, which comprised 1.5% of the body weight of the recipient. The recipient had an excellent recovery without any major complications, and was discharged 35 days after the operation. At 15 months after the operation, the patient has shown no signs of rejection while using FK506 and prednisolone as immunosuppressants. The progression of symptomatic PBC can be predicted, and the timing of the transplantation can be easily determined. In addition, the results of liver transplantation for PBC are good. Therefore, adult living related partial liver transplantation is an excellent treatment for primary biliary cirrhosis.

Bilirubin↗
PubMed1997

Neuropathic pain and prolonged regional inflammation as two distinct symptomatological components in complex regional pain syndrome with patchy osteoporosis--a pilot study.

To reappraise symptomatology of complex regional pain syndrome (CRPS), we investigated the clinical symptoms of seven patients with CRPS who showed associated patchy osteoporosis. The incidence of moderate to severe spontaneous pain, burning pain, mechanical allodynia was higher in patients with significant nerve injury than in those without. Periarticular tenderness adjacent to osteoporotic bones, abnormalities of blood flow, edema and impairment of motor function were seen in both groups of patients. Our clinical observations of patients with CRPS associated with patchy osteoporosis suggest that CRPS may have the following two distinct components: (1) neuropathic pain that includes severe spontaneous pain or severe persistent mechanical allodynia and (2) prolonged regional inflammation, the early phase of which could be indicated by positive inflammatory symptoms of pain (tenderness), heat, redness, swelling and loss of function and their alleviation with corticosteroids.

Adult↗
PubMed1997

[The effect of low-dose prostaglandin E1 on serum and urinary fluoride concentrations in patients anesthetized with sevoflurane].

We investigated the effects of low-dose prostaglandin E1 (PGE1) on serum and urinary concentrations of inorganic fluoride in 39 adult patients undergoing upper abdominal surgery. Anesthesia was maintained with a combination of N2O-O2-sevoflurane and thoracic epidural anesthesia. Twenty-two patients received infusion of PGE1 at a rate of 0.02 micrograms.kg-1.min-1 throughout surgery. Seventeen patients served as control by not receiving PGE1. Serum inorganic fluoride concentrations (FB) were determined before the induction of anesthesia and 0, 2 and 24 hours after the end of anesthesia. Urinary inorganic fluoride concentrations (FU) were determined before the induction of anesthesia, and 0, 24 and 48 hours after the end of anesthesia. These was no difference between PGE1 group and control group in anesthetic dose (MAC hours) of sevoflurane. In both groups, FB peaked at the end of anesthesia. In PGE1 group, UB peaked at the end of anesthesia, while in control group, it peaked 24 hours after anesthesia. There were differences between groups neither in FB nor in FU throughout the study period. The relationships between anesthetic dose and fluoride concentrations, however, differed significantly between the groups. In control group FB values of 0, 2 and 24 hours after anesthesia correlated positively with MAC hours, respectively, while in PGE1 group they did not. Similarly in control group, FU values of 24 and 48 hours after anesthesia correlated positively with MAC hours, respectively, while in PGE1 group, they did not. Thus in patients receiving high-dose sevoflurane, FB and FU tended to be lower in PGE1 group than in control group. In contrast, in PGE1 group, urinary excretion of fluoride during surgery correlated positively with MAC hours, while in control group, it did not. Urinary fluoride excretion during surgery was significantly greater in PGE1 group than in control group. These results suggested that PGE1 might prevent elevation of serum and urinary fluoride concentrations in patients receiving high-dose sevoflurane. This effect might result from enhanced urinary excretion of fluoride with PGE1.

Abdomen↗
PubMed1996

Atropine premedication attenuates heart rate variability during high thoracic epidural anesthesia.

BACKGROUND: Atropine premedication is used as it possesses an anticholinergic effect on the cardiac autonomic nervous system (CANS). The aim of this study was to investigate the effect of atropine premedication on the CANS during thoracic epidural anesthesia (TEA) by assessing power spectral analysis of heart rate (HR) variability. METHOD: Female patients (n = 28) undergoing elective mammary biopsy were randomly allocated into two groups; one received intramuscular premedication of 0.01 mg/kg of atropine 30 min before the procedure (group A: n = 14), and the other did not (group N: n = 14). Each electrocardiogram was digitally recorded before and during TEA, and played back off-line to detect R-R intervals. As a power spectrum required R-R intervals of 256 s, this was analysed before TEA and repeated thereafter for 25 min. The spectra were quantified by determining the peak areas of the spectral density by integrating low frequency (Lo: 0.04-0.15 Hz) and high frequency (Hi: 0.15-0.40 Hz) bands as they showed sympathetic and parasympathetic nervous activity in the CANS. The neural balance was assessed by calculating Hi:Lo ratio. RESULTS: Decreases in Lo and increases in Hi:Lo ratio were observed, suggesting sympathectomy and vagotonia with TEA in both groups. For 10 min after commencement, TEA maintained Hi:Lo ratios lower in group A than in group N, suggesting a vagolytic effect of premedication with atropine. With TEA, cardiac slowing was observed, which was dependent on the level of dermal analgesia. CONCLUSION: Power spectral analysis revealed that TEA had the effect of making CANS relatively vagotonic, and that atropine premedication would attenuate the effect of TEA.

Anesthesia, Epidural↗
PubMed1996

Self-limiting enhancement by nitric oxide of oxygen free radical-induced endothelial cell injury: evidence against the dual action of NO as hydroxyl radical donor/scavenger.

1. The effects of oxygen free radical scavengers and endothelial cell-derived nitric oxide (EDNO) on the death of porcine cultured aortic endothelial cells exposed to exogenous superoxide-[xanthine (0.4 mM)/xanthine oxidase (0.04 unit ml-1) + diethylenetriaminepentaacetic acid (DTPA, 10 microM)] or hydroxyl radical-generating system(s) [superoxide generating system+ferric iron (Fe3+, 0.1 mM) or peroxynitrite (0-100 microM)] have been evaluated. 2. Spin trapping studies using 5,5-dimethyl-l-pyrroline-N-oxide (DMPO) with electron paramagnetic resonance spectrometry were also conducted to determine qualitatively the oxidant species generated by the oxidant generating systems. 3. Endothelial cell injury provoked by the exogenous superoxide generating system was inhibited by catalase, DTPA and a hydroxyl radical scavenger (dimethyl sulphoxide, DMSO), but not by superoxide dismutase (SOD). Addition of Fe3+ to the superoxide generating system enhanced the cell injury. These suggested that the direct cytotoxicity of exogenous superoxide is limited, and that endogenous transition metal-dependent hydroxyl radical formation is involved in the cell injury. 4. An inhibitor of the constitutive NO-pathway, NG-monomethyl-L-arginine, did not influence cell injury induced by the superoxide generating system, suggesting that basal NO production is not responsible for the cytotoxicity. 5. Stimulation of endothelial cells with bradykinin enhanced cell injury provoked by the exogenous superoxide generating system, but not by the exogenous hydroxyl radical generating system. The enhancement by bradykinin was inhibited by NG-monomethyl-L-arginine and bradykinin B2-receptor antagonist, D-Arg-[Hyp3, Thi5,8, D-Phe7] bradykinin, suggesting that an interaction of NO with superoxide is involved in the enhanced cytotoxicity. A possible intermediate of this reaction, peroxynitrite, also caused endothelial cell injury in a concentration-dependent manner. 6. The modulatory effects of NO on hydroxyl radical-like activity (= formaldehyde production) from the superoxide generating system was also evaluated in a cell-free superoxide/NO generating system, consisting of xanthine/xanthine oxidase, DTPA, DMSO, and various amounts of a spontaneous NO generator, sodium nitroprusside (SNP) and were compared with those of Fe3+. At doses up to 10 microM, SNP concentration-dependently increased the formaldehyde production while the higher concentrations of SNP decreased. The maximum amount of formaldehyde produced by SNP was 5 fold less than that produced by Fe3+ (0.1 mM). Peroxynitrite-induced formaldehyde formation was concentration-dependently inhibited by SNP. 7. We conclude that agonist-stimulated but not basal NO production acts as cytotoxic hydroxyl radical donor as well as the endogenous transition metal when endothelial cells are exposed to exogenous superoxide anion, while the modulatory effect of EDNO is limited by a secondary reaction with hydroxyl radicals.

Administration, Topical↗
PubMed1996

Heart rate variability during artificial ventilation and apnea in brain-damaged rabbits.

The effect of artificial ventilation, apnea, and norepinephrine administration on heart rate variability was determined in brain-damaged rabbits. Electrocardiographic R-R intervals and circulatory variables were measured for 5 min at three different ventilatory frequencies, including apnea under isoflurane general anesthesia. The same measurements were repeated after brain damage was inflicted by an inflated intracranial balloon. In control rabbits (n = 8) and in those receiving norepinephrine (n = 8), power spectral analysis of R-R intervals was repeated, and spectral components of low (LF: 0.04-0.09 Hz), mid (MF: 0.09-0.15 Hz), and high (HF: 0.15-0.40 Hz) frequency band areas were assessed. LF + MF (P < 0.05) increased during apnea, whereas HF did not change under general anesthesia. However, after brain damage in both groups LF + MF did not change, whereas HF was depressed (P < 0.05). There was no intergroup difference in decreases of HF/(LF + MF) (P < 0.05) during apnea under either condition. Norepinephrine increased heart rate and arterial pressure (P < 0.05) but did not produce any intergroup difference in the spectral components. We suggest that sympathovagal balance is apt to be sympathotonic during apnea under general anesthesia, whereas it is vagolytic with brain damage.

Animals↗
PubMed1996

The dehydrofluorinated product of sevoflurane by soda lime reacts with ethanol to produce two products.

Dehydrofluorinated sevoflurane produced by soda lime reacted with methanol to produce methoxylated compounds. It is expected that dehydrofluorinated sevoflurane may react with ethyl alcohol in a patient who has recently ingested alcohol. In a closed vessel system and a model lung with circle absorber, sevoflurane, soda lime and ethanol were reacted at 25 degrees C. The breakdown products of sevoflurane in the gas phase were analyzed by gas chromatography and mass spectrometry. The ethoxylated compounds of dehydrofluorinated sevoflurane [fluoromethyl 2-ethoxy-2,2-difluoro-1-(trifluoromethyl)ethyl ether] and its dehydrofluorinated compound [fluoromethyl 2-ethoxy-2,2-fluoro-1-(trifluoromethyl)vinyl ether] were detected in the mixture of sevoflurane and soda lime in the presence of ethanol. In the closed vessel, the concentrations of these compounds were 69.4 +/- 6.6 ppm and 79.3 +/- 8.8 ppm, respectively, at 120 min in the presence of 11.2 mg/l of ethanol. These concentrations were dependent on the ethanol concentration. These compounds were also detected in the closed anesthetic circuit having a model lung by 180 minutes of circulation of 1.5% sevoflurane and 0.56 mg/l of ethanol with 200 ml/min carbon dioxide gas through soda lime: 24.2 +/- 4.0 ppm and 21.4 +/- 0.9 ppm, respectively. Dehydrofluorinated sevoflurane reacts with ethanol at concentrations that are within the range that may be encountered in a patient who has recently ingested alcohol to produce an ethoxylated compound, and this ethoxylated compound undergoes dehydrofluorination by soda lime.

Anesthesia, Closed-Circuit↗
PubMed1996

[Hemilateral hydrothorax and atelectasis during laparoscopic Nissen fundoplication].

A 57-year-old woman, weighing 75 kg, with gastroesophageal sliding hernia, received laparoscopic Nissen fundoplication under general anesthesia. Although artificial ventilation was carried out uneventfully when the surgery started, sudden decreases in SpO2 and thoraco-pulmonary compliance were noted after insufflation of CO2. Breath sound was not audible on the left lung. We suspected that inadvertent pneumothorax was produced, but chest X-ray and transesophageal echocardiography at the end of surgery revealed the presence of left hemilateral hydrothorax with pulmonary atelectasis. She was ventilated artificially and given diuretics and albumin solution for 3-days before extubation. We speculated on two reasons for the event: a possibility of perforation of the diaphragm manipulated by surgeons, and that of transition of fluid used for irrigation just below the diaphragm. Pulmonary atelectasis could be induced with hemilateral lung ventilation because cephalad shifting of the diaphragm might follow the intraperitoneal insufflation. We conclude that laparoscopic surgery with insufflation of gas and irrigation with fluid requires careful attention if the laparoscopic surgery is sustained with insufflation and irrigation.

Anesthesia, General↗
PubMed1996

[Serial changes of atrial natriuretic peptide and brain natriuretic peptide during cesarean section under spinal anesthesia].

Both atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) are considered to play a role in regulation of body fluid volume and blood pressure. Serial changes of their plasma concentrations are known to reflect blood volume. In this study, we investigated the serial changes in maternal blood concentrations of ANP and BNP in those who underwent cesarean section under spinal anesthesia. Blood samples were obtained before anesthesia, before surgery, at the end of surgery, and on the next morning. Samples were also compared with those from normal pregnant women. Throughout the cesarean section, ANP did not show any significant changes, while BNP remained within normal ranges during anesthesia and increased on the next morning. We concluded that ANP and BNP were regulated differentially, and that BNP reflected blood volume significantly during and after spinal anesthesia.

Adult↗
PubMed1995

Inhibitory effect of sevoflurane on nitric oxide release from cultured endothelial cells.

We investigated the effect of sevoflurane (fluoromethyl-2,2,2-trifluoro-1-(trifluoromethyl) ethylether) on intracellular calcium concentration ([Ca2+]i) and nitric oxide (NO) release from cultured porcine aortic endothelial cells using fura-2 fluorometry, and direct (ESR spectrometry with NO-trapping by 2-(4-carboxyphenyl)-4,4,5,5-tetramiethylimidazoline-1-oxyl 3-oxide) or indirect (nitrite accumulation measured by Greiss reaction) NO measurement. Sevoflurane alone did not change resting [Ca2+]i, but diminished bradykinin-induced transient increase in [Ca2+]i in a concentration-dependent manner. The inhibitory effect of sevoflurane on bradykinin-induced transient rise in [Ca2+]i was larger than that of a non-selective Ca2+ channel blocker (CO2+). Application of sevoflurane following bradykinin-evoked [Ca2+]i transient diminished [Ca2+]i significantly, while bradykinin B2 receptor antagonist (D-Arg-[Hyp3, Thi5,8, D-Phe7] bradykinin) or CO2+ abolished it. Sevoflurane impaired nitrite accumulation stimulated by bradykinin, and reduced the amount of NO released from endothelial cells. Our results indicate that the negative effect of sevoflurane appears to be due to the inhibition of bradykinin-induced Ca2+ efflux from endoplasmic stores and Ca2+ influx through membrane Ca2+ channels.

Analysis of Variance↗
PubMed1995

Inhibitory effect of lidocaine on cultured porcine aortic endothelial cell-dependent antiaggregation of platelets.

BACKGROUND: Vascular spasm is a well-known complication during vascular surgery. Topical lidocaine is frequently used to prevent this spasm. However, the effects of lidocaine on the endothelium-dependent antiaggregation are not clear. METHODS: The aggregation of platelet-rich plasma (PRP) obtained from healthy volunteers was measured by the turbidimetric technique at 37 degrees C. (1) Cultured porcine aortic endothelial cells were preincubated with lidocaine (3.7 microM to 37 mM), NG-methyl-L-arginine (300 microM), or indomethacin (10 microM) for 30 min. The preincubation medium was exchanged with a medium containing +/- 1 microM bradykinin for 1-min stimulation of endothelial cells. One hundred microliters of the supernatant was then added to PRP (750 micro1) just after stimulation of PRP with collagen (4 micrograms/ml). (2) Authentic nitric oxide (NO) or prostacyclin (PGI2) was applied to collagen-stimulated PRP with or without lidocaine (100 micrograms/ml). RESULTS: (1) The supernatant from endothelial cells without bradykinin stimulation showed "basal" antiaggregation (13.8 +/- 3.2%; n = 6). Bradykinin enhanced the antiaggregation (100 +/- 0%; n = 6). NG-methyl-L-arginine or indomethacin (antagonists of NO or PGI2) inhibited the bradykinin-evoked antiaggregation (10.3 +/- 2.1% and 13.6 +/- 3.7%, respectively; n = 6). Simultaneous preincubation of both agents completely blocked the effect (-4.2 +/- 2.8%; n = 6). Lidocaine failed to influence basal antiaggregation, but it inhibited bradykinin-stimulated antiaggregation in a concentration-dependent manner (concentration causing 50% inhibition = 108 +/- 41 microM; n = 6). (2) In contrast, lidocaine did not shift the 50% effective concentration of NO (control, 1.3 +/- 0.1 microM vs. lidocaine, 1.6 +/- 0.1 microM) or PGI2 (control, 405 +/- 54 nM vs. lidocaine, 257 +/- 41 nM) for antiaggregation. CONCLUSIONS: Our results suggest that lidocaine has an inhibitory effect on antiaggregation derived from endothelial cells, caused by the inhibition of NO and PGI2 released from endothelial cells.

Animals↗
PubMed1995

Endotracheal intubation under image guidance for a child with tracheal stenosis.

A case of successful endotracheal intubation using an image intensifier in a 9-year-old boy with tracheal stenosis was reported. After the induction of anesthesia, the trachea was observed by use of mobile surgical X-ray apparatus under artificial ventilation using a face mask. Because the tracheal wall of the stenotic part was smooth and seemed soft, we selected a plain 5.5 mm diameter endotracheal tube and intubated under observation using an image intensifier. We observed the tube pass through the stenotic part of the trachea without difficulty. We consider that endotracheal intubation under image guidance is useful in a patient with tracheal stenosis.

Adenocarcinoma, Papillary↗
PubMed1995

[Interaction between opiate subtypes and serotonin in suppressing noxiously evoked activity of WDR neurons].

The present study examined interactions between mu and delta opiate subtypes and serotonin. Noxious activity evoked by radiant heat (51 degrees C, 8 sec) was extracellularly recorded from single discriminated wide dynamic range (WDR) neurons in decerebrate spinally transected cats. DAGO (mu selective opioid agonist) 1 microgram or DPDPE (delta selective opioid agonist) 30 micrograms was combined with serotonin (n = 6 each) 250 micrograms. The dose of each drug by itself when administered intrathecally produced no suppression of noxiously evoked activity. Although the combination of DAGO and serotonin produced no significant suppression of noxiously evoked activity, DPDPE and serotonin produced significant suppression to 72.8 +/- 8.0 % (mean +/- SEM) of control values (P < 0.01). Intravenously administered naloxone 0.1 mg reversed the suppression produced by the DPDPE-serotonin combination. Our results suggest that combinations of serotonin and delta selective opiates may be more effective in suppressing noxiously evoked activity than combinations with mu selective opiates.

Animals↗
PubMed1994

Usefulness of transesophageal echocardiography for guiding pulmonary artery catheter placement in the operating room.

The usefulness of transesophageal echocardiography (TEE) for guiding the placement of a pulmonary artery (PA) catheter was evaluated in 31 patients (TEE group); 31 patients who were treated before TEE guidance was used (control group). In the control group, use of the PA catheter was abandoned in two patients; because of an unstable condition and marked arrhythmias, respectively. The key findings for TEE guidance were: (1) pulsatile to-and-fro movement of the balloon, i.e., "shuttle movement" and (2) loss of shuttle movement at wedging of the balloon, i.e., "anchoring sign." When the PA catheter did not enter the right vertricle (RV), the balloon was found to be in the inferior vena cava or the right atrium (RA) without shuttle movement. Coiling of the catheter was suggested in the latter situation. Coiling also occurred in the RV, often associated with frequent arrhythmias. These findings indicate that the catheter should be withdrawn once. TEE allowed for readjustment of the catheter tip position by enabling the balloon to be wedged twice. An excessively deep placement of the catheter tip was seen in 5 of the controls, but in none of the TEE group. Biplane TEE was found to be advantageous for guiding PA catheter placement and for visualizing the RV inflow and outflow tract in a single view, with the shuttle movement of the balloon in its long axis. TEE acts as an "eye" in the operating room, as does fluoroscopy, enabling smooth placement of the PA catheter.

Adult↗