Sinus node dysfunction associated with discontinuation of cilostazol in a patient taking atenolol.
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Adrenergic beta-Antagonists↗
Biomedical subjects
T Kumazawa
Publications and source records attributed to T Kumazawa.
Nitrous oxide decreases shivering threshold in rabbits less than isoflurane.
BACKGROUND: Comparable minimum alveolar concentration (MAC) fractions of volatile anaesthetics produce similar thermoregulatory impairment. Nitrous oxide, however, decreases the vasoconstriction threshold less than sevoflurane or isoflurane. We tested the hypothesis that nitrous oxide also decreases shivering threshold less than isoflurane alone or in combination. METHODS: Twenty-four rabbits were assigned randomly to one of three 0.3 MAC anaesthetic regimens: (i) nitrous oxide 69%; (ii) nitrous oxide 35% and isoflurane 0.3%; or (iii) isoflurane 0.6%. Body temperature was lowered by perfusing 10 degrees C water through a U-shaped thermode positioned in the colon. Shivering was evaluated by inspection. RESULTS: The rabbits anaesthetized with nitrous oxide alone shivered at 37.0 (0.5) degrees C (P<0.01 vs other groups). In those given the nitrous oxide and isoflurane combination, the shivering threshold was 36.4 (0.5) degrees C and that in the isoflurane group was 35.9 (0.4) degrees C. CONCLUSION: This study indicates that nitrous oxide reduces the shivering threshold less than isoflurane.
Anesthetics, Inhalation↗
Effects of nicorandil on myocardial function and metabolism in the post-ischaemic reperfused heart with or without inhalation anaesthetics.
BACKGROUND: Nicorandil, which is an ATP-sensitive K channel opener, has been reported to protect the ischaemic myocardium. However, its interaction with inhalation anaesthetics on the ischaemic myocardium has not been well elucidated. So, we have investigated whether isoflurane or sevoflurane modify the effects of nicorandil on cardiac function and metabolism in the rat heart-lung preparation. METHODS: Animals were allocated to 4 groups as follows: Control group, no drug; Nic group, nicorandil; Nic+Iso group, nicorandil and isoflurane; Nic+Sev group, nicorandil and sevoflurane. Seven minutes after the start of perfusion, nicorandil was administered and 10 min after the start of perfusion, the heart was rendered globally ischaemic for 10 min, and then the heart was reperfused for 10 min. RESULTS: LVdP/dt max in the Nic group was higher than those in the other groups. Right atrial pressure in the Nic+Iso and Nic+Sev groups was significantly higher than in the Control and Nic groups. Myocardial ATP in the Nic group was higher than in the other groups. DHBA levels in the perfusate in the Nic and Nic+Iso groups were lower than those in the Control and Nic+Sev groups, but those in the Nic+Sev group were higher than those in the other groups. CONCLUSIONS: Nicorandil improved post-ischaemic cardiac function and preserved high-energy phosphates. However, these beneficial effects of nicorandil were abolished by the combination with isoflurane or sevoflurane. In addition, sevoflurane increased hydroxyl radical formation in the post-ischaemic reperfused heart.
Adenosine Triphosphate↗
Sensitive determination of four general anaesthetics in human whole blood by capillary gas chromatography with cryogenic oven trapping.
Four general anaesthetics, sevoflurane, isoflurane, enflurane and halothane, in human whole blood, have been found measurable with very high sensitivity by capillary gas chromatography-flame ionization detection (GC-FID) with cryogenic oven trapping upon injection of headspace (HS) vapor sample. To a 7-ml vial, containing 0.48 ml of distilled water and 20 microl of internal standard solution (5 microg), a 0.5-ml of whole blood sample spiked with or without anaesthetics, was added, and the mixture was heated at 55 degrees C for 15 min. A measure of 10 ml HS vapor was injected into the GC in the splitless mode at -40 degrees C oven temperature, which was programmed up to 250 degrees C. All four peaks were clearly separated; no impurity peaks were found among their peaks. Their extraction efficiencies were about 10%. The calibration curves showed good linearity in the range of 0.5-20 microg/ml; their detection limits were 10-100 ng/ml, which are almost comparable to those by previous reports. The coefficients of intra-day and day-to-day variations were 6.5-9.8 and 7.3-17.2%, respectively. Isoflurane or enflurane was also measured from whole blood samples in which three volunteers inhaled each compound.
Adult↗
Cleavage of the C-C linkage between the sugar and the aglycon in C-glycosylphloroacetophenone, and the NMR spectral characteristics of the resulting di-C-glycosyl compound.
The treatment of unprotected mono-C-beta-D-glucopyranosylphloroacetophenone with a cation-exchange resin in anhydrous acetonitrile afforded both a phloroacetophenone and a di-C-beta-D-glucopyranosylphloroacetophenone. Treatment of an unprotected mono-C-(2-deoxy-beta-D-arabino-hexopyranosyl)phloroacetophenone (mono-C-2-deoxy-beta-D-glucopyranosylphloroacetophenone) also afforded both the aglycon and di-C-(2-deoxy-beta-D-arabino-hexopyranosyl)phloroacetophenone. The reaction mixtures were acetylated, and the structures of the isolated products were determined by NMR spectroscopy. This is the first demonstration of the formation of a di-C-glycosyl compound during the chemical cleavage of the C-C linkage between the sugar and the aglycon in an aryl C-glycosyl derivative.
Acetophenones↗
Novel glycosylation of the nitroxyl radicals with peracetylated glycosyl fluorides using a combination of BF(3) x OEt(2) and an amine base as promoters.
Glycosylation of the nitroxyl radicals, 4-acetoxy-2,2,6,6-tetramethylpiperidin-1-oxyl (4-acetoxy-TEMPO) and 3-carbamoyl-2,2,5,5-tetramethylpyrollin-1-oxyl (3-carbamoyl-PROXYL) with peracetylglycosyl fluoride as the glycosyl donor, in the presence of boron trifluoride diethyl etherate (BF(3) x OEt(2)) and an amine base afforded the corresponding hydroxylamine-O-glycosides in 25-100% yields.
Amines↗
Synthesis of 8-C-glucosylflavones.
The syntheses of orientin, parkinsonin A, isoswertiajaponin, and parkinsonin B, which are 8-C-beta-D-glucopyranosyl-3',4',5,7-tetrahydroxyflavone, 5-methyl orientin, 7-methyl orientin, and 5,7-dimethyl orientin, respectively, are reported herein. The C-glucosyl phloroacetophenone derivatives were obtained via a regio- and stereoselective O-->C glycosyl rearrangement. Aldol condensation of the C-glucosyl phloroacetophenone derivatives with 3,4-bisbenzyloxybenzaldehyde afforded the corresponding C-glucosylchalcones. Construction of the flavone system by reaction with I(2)-Me(2)SO, followed by the elimination of the 5-benzyl protecting group in the flavone structure, yielded an orientin derivative and a isoswertiajaponin derivative. Methylation of the orientin derivatives with dimethyl sulfate afforded the parkinsonin A derivative, the isoswertiajaponin derivative, and the parkinsonin B derivative. Finally, hydrogenolysis of these C-glucosylflavone derivatives led to the four 8-C-glucosylflavones. The NMR spectra of these C-glucosylflavones showed a duplication of signals corresponding to a major rotamer, along with a minor one. Based on NOESY experiments in Me(2)SO at ambient temperature, they adopted conformations in which the H-2"and H-4" protons in the glucose moiety were oriented toward the B-ring in the flavone structure.
Antioxidants↗
Sensitive determination of pethidine in body fluids by surface ionization organic mass spectrometry.
We have presented a simple and sensitive method for determining pethidine, a narcotic analgesic drug in body fluids by gas chromatography (GC)/surface ionization organic mass spectrometry (SIOMS). Good linearity was obtained in the range of 0.625-25 ng/ml of whole blood and urine by mass chromatography, and in the range of 0.05-2 ng/ml of whole blood by selected ion monitoring (SIM). Pethidine and diphenylpyraline (internal standard) were extracted from body fluids with Bond Elut Certify cartridges; their recoveries were above 95%. The detection limits (signal-to-noise ratio=3) were estimated to be 0.2 ng/ml of whole blood or urine by mass chromatography, 0.02 ng/ml of whole blood by SIM.
Analgesics, Opioid↗
Synthesis of C-mannopyranosylphloroacetophenone derivatives and their anomerization.
The reaction of 2,3,4-tri-O-benzyl-alpha-L-rhamnopyranosyl fluoride (6-deoxy-2,3,4-tri-O-benzyl-alpha-L-mannopyranosyl fluoride) with 2,4-dibenzylphloroacetophenone, in the presence of boron trifluoride.diethyl etherate, afforded both the 3-C-alpha-L- and the 3-C-beta-L-rhamnopyranosylphloroacetophenone derivatives. The 3-C-alpha-L-rhamnoside was produced as a major product, while the 3-C-beta-L-rhamnoside was produced as a minor product via anomerization of the 3-C-alpha-L-rhamnoside. Alternatively, the reaction of 2,3,4,6-tetra-O-benzyl-alpha-D-mannopyranosyl fluoride with 2,4-dibenzylphloroacetophenone afforded both the 3-C-alpha-D- and the 3-C-beta-D-mannnopyranosylphloroacetophenone derivatives under identical conditions. The 3-C-beta-D-mannoside was produced as a major product via anomerization of the 3-C-alpha-D-mannoside during the reaction. These differences in composition result apparently from the magnitude of the 1,3-diaxial interactions between the C-3 and C-5 positions in these sugar moieties.
Acetophenones↗
Optical recordings of taste responses from fungiform papillae of mouse in situ.
Single taste buds in mouse fungiform papillae consist of approximately 50 elongated cells (TBCs), where fewer than three TBCs have synaptic contacts with taste nerves. We investigated whether the non-innervated TBCs were chemosensitive using a voltage-sensitive dye, tetramethylrhodamine methyl ester (TMRM), under in situ optical recording conditions. Prior to the optical recordings, we investigated the magnitude and polarity of receptor potentials under in situ whole-cell clamp conditions. In response to 10 mM HCl, several TBCs were depolarized by approximately 25 mV and elicited action potentials, while other TBCs were hyperpolarized by approximately 12 mV. The TBCs eliciting hyperpolarizing receptor potentials also generated action potentials on electrical stimulation. A mixture of 100 mM NaCl, 10 mM HCl and 500 mM sucrose depolarized six TBCs and hyperpolarized another three TBCs out of 13 identified TBCs in a taste bud viewed by optical section. In an optical section of another taste bud, 1 M NaCl depolarized five TBCs and hyperpolarized another two TBCs out of 11 identified TBCs. The number of chemosensitive TBCs was much larger than the number of innervated TBCs in a taste bud, indicating the existence of chemosensitivity in non-innervated TBCs. There was a tendency for TBCs eliciting the same polarity of receptor potential to occur together in taste buds. We discuss the role of non-innervated TBCs in taste information processing.
Action Potentials↗
Pulmonary carbon dioxide embolism during laparoscopic cholecystectomy.
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Aged↗
Effects of epidural fentanyl and intravenous flurbiprofen for visceral pain during cesarean section under spinal anesthesia.
PURPOSE: Despite adequate levels of sensory blockade, patients sometimes complain of abdominal pain during cesarean section performed under spinal anesthesia. The aim of this study was to evaluate the effects of epidural fentanyl and intravenous flurbiprofen on visceral pain during cesarean section in patients having spinal anesthesia. METHODS: Thirty ASA physical status I and II patients undergoing elective cesarean section were studied. Spinal-epidural anesthesia was performed in all groups. Group A received no additional analgesics, group B received epidural fentanyl 100 mug, and group C received flurbiprofen 50 mg i.v. immediately after the delivery. Postdelivery, intraoperative visceral pain was evaluated by using the visual analog scale. Incidence and visual analog scale scores of visceral pain and incidence of intraoperative nausea and vomiting were obtained from each patient. RESULTS: Visual analog scale scores of pain were significantly lower in group B than in the other groups (P < 0.05). The incidence of nausea was comparable in all groups. The incidence of intraoperative vomiting was lower in group C than in the other groups (P < 0.05). CONCLUSION: Epidural fentanyl, but not intravenous flurbiprofen, decreases the incidence and severity of visceral pain during cesarean section.
Journal Article↗
Sevoflurane reduces dysrhythmias during reperfusion in the working rat heart.
PURPOSE: The effects of sevoflurane on myocardial reperfusion injury have not been well studied. The purpose of this study was to determine the effects of sevoflurane on myocardial function, arrhythmia, and metabolism during reperfusion in an isolated working rat heart model. METHODS: Thirty-two hearts were divided into four groups according to the timing of 2.5% sevoflurane administration: group I, control, no sevoflurane; group II, sevoflurane administered only before ischemia; group III, sevoflurane only during reperfusion; group IV, sevoflurane during the whole study period. Myocardial contractility, myocardial ATP, lactate, and glycogen levels were assessed in the reperfusion period following global heart ischemia of 15 min duration. The incidence and duration of ventricular fibrillation were also observed in the reperfusion period. RESULTS: There was no difference in cardiac output and left ventricular dP/ dt max among the four groups at 10, 15, and 20 min after reperfusion. There was no difference in myocardial ATP, lactate and glycogen contents between the groups. The incidences of ventricular fibrillation during reperfusion were 100%, 63%, 100%, and 25% (P < 0.05 vs control), and the durations of ventricular fibrillation during reperfusion were 375 +/- 269, 104 +/- 98 (P < 0.05 vs control), 303 +/- 189, and 93 +/- 245 (P < 0.05 vs control) in groups I, II, III, and IV, respectively (mean +/- SD). CONCLUSION: The administration of sevoflurane prior to reperfusion appears to provide myocardial protection, as assessed by reduced dysrhythmias during reperfusion.
Journal Article↗
Soybean sterol composition and utilization by Phytophthora sojae.
The sterol fraction of Glycine max (soybean) was found to contain a mixture of 13 major sterols which differed dramatically in composition between seeds and shoots. Typical C4-desmethyl Delta(5)-sterols, including sitosterol, predominate the sterol mixture of shoots, whereas C4-methyl sterol intermediates, cycloartenol and 24(28)-methylene cycloartanol, accumulate in seeds. The significance of modified sterol profile of shoot compared to seed was relevant to the physiology of Phytophthora sojae, a phytopathogen of soybean shown to be auxotrophic for sterol. Sterols native to the host plant containing a C4-methyl group, such as cycloartenol, were not utilized by the fungus. Alternatively, all Delta(5)-sterols added to the culture media of P. sojae supported normal growth and promoted viable oospore production. The results demonstrate the importance of sterols in plant-fungal interactions and offer the possibility of bioengineering the phytosterol pathway for resistance to phytopathogens which scavenge specific sterols of the host plant to complete the life cycle.
Molecular Structure↗
Atropine prevents midazolam-induced core hypothermia in elderly patients.
STUDY OBJECTIVE: To test the hypothesis that core temperature is well preserved when atropine and midazolam are combined. DESIGN: Randomized, blinded study. SETTING: Department of Anesthesia, Yamanashi Medical University. PATIENTS: 40 elderly, ASA physical status I and II patients (aged more than 60 years). INTERVENTIONS: Patients were randomly assigned (n = 10 per group) to premedication with: 1) saline control; 2) midazolam 0.05 mg/kg; 3) atropine 0.01 mg/kg; and 4) midazolam 0.05 mg/kg combined with atropine 0.01 mg/kg. All premedication was given on the ward at approximately 8:30 am, approximately 30 minutes before induction of anesthesia. MEASUREMENTS AND MAIN RESULTS: Core temperatures were measured at the right tympanic membrane. Mean skin temperature was calculated as 0.3 x (T(chest) + T(arm)) + 0.2 x (T(thigh) + T(calf)). Fingertip perfusion was evaluated using forearm minus fingertip and calf minus toe, skin-surface temperature gradients. Temperatures were evaluated at the time of premedication and 30 minutes later, just before induction of anesthesia. Core temperature remained nearly constant in the control patients (0.1 +/- 0.2 degrees C; mean +/- SD), whereas it decreased significantly in the patients given midazolam alone (-0.3 +/- 0.1 degrees C). Atropine alone increased core temperature (0.3 +/- 0.2 degrees C), although the increase was not statistically significant. The combination of midazolam and atropine attenuated the hypothermia induced by midazolam alone (0.0 +/- 0.2 degrees C). Initial skin-temperature gradients exceeded 0 degrees C in all groups, indicating that the patients were vasoconstricted. The gradients were unchanged by premedication with saline or atropine. Midazolam significantly decreased the gradient (-1.8 +/- 1.1 degrees C), as did the combination of midazolam and atropine (-1.4 +/- 0.9 degrees C). CONCLUSIONS: The thermoregulatory effects of benzodiazepine receptor agonist and cholinergic inhibitors oppose each other, and the combination leaves core temperature unchanged.
Aged↗
Intravenous ketamine attenuates arterial pressure changes during the induction of anaesthesia with propofol.
BACKGROUND AND OBJECTIVE: To investigate whether the administration of ketamine before induction with propofol produces a smaller decrease in arterial pressure. METHODS: Twenty-two patients were assigned to one of two groups to receive either propofol with ketamine (n = 11) or propofol alone (n = 11, control). Anaesthesia was induced with 2 mg kg-1 propofol and 0.5 mg kg-1 ketamine or 2 mg kg-1 propofol alone. Ketamine was administered 1 min prior to induction with propofol. Immediately after induction with propofol, vecuronium (0.15 mg kg-1) was administered. Four minutes after administration of vecuronium, tracheal intubation was performed. Anaesthesia was maintained using sevoflurane (0.5%) in 66% nitrous oxide until 3 min after intubation. Systolic, diastolic and mean arterial pressure and heart rate were recorded on arrival, directly before induction with propofol, prior to tracheal intubation, immediately after intubation and at 3 min after intubation. RESULTS AND CONCLUSIONS: Administration of ketamine before induction with propofol preserved haemodynamic stability compared with induction with propofol alone.
Anesthesia↗
Effects of cibenzoline on cardiac function and metabolism in the rat heart--lung preparation.
BACKGROUND AND OBJECTIVE: Although there is concern that cibenzoline, an antidysrhythmic drug for the treatment of ventricular and supraventricular dysrhythmias, may be associated with dose-dependent inhibition of myocardial contractility there are few reports about the relationship between myocardial metabolism and cardiac function when it is used. The present study was designed to investigate the effects of cibenzoline on cardiac function and metabolism. The effects of cibenzoline on cardiac function and myocardial metabolism were assessed in the isolated rat heart-lung preparation. METHODS: Thirty-two male Wistar-ST rats were divided into four groups: control, and those to receive cibenzoline, either 300, 900 or 3000 ng mL(-1). The cibenzoline was administered into the perfusate 5 min after the start of perfusion. Heart rates in the 3000 ng mL(-1) group were significantly lower than those in the control group. Cardiac output in the 3000 ng mL(-1) group at 15 and 30 min was significantly lower than in the control group. In all groups, values for %LV dP/dt max (the ratio of values at each time to those at 5 min) at 20, 25, 30 min were significantly higher than at 5 min. Myocardial adenosine triphosphate concentration in the 3000 ng mL(-1) group was significantly lower than in controls. There was no difference between groups in the lactate/pyruvate ratio. CONCLUSION: The therapeutic range of cibenzoline has few effects on cardiac function and metabolism, although concentrations 10 times greater may cause a deterioration in myocardial metabolism.
Adenosine Diphosphate↗
Effects of glibenclamide on hydroxyl radical formation in the postischaemic reperfused heart with or without inhalation anaesthetics.
BACKGROUND AND OBJECTIVE: We investigated whether glibenclamide (glyburide) affects myocardial metabolism and hydroxyl radical formation in the rat heart-lung preparation with or without inhalation anaesthetics. METHODS: Thirty-seven male Wistar rats were allocated to four groups: (a) control group (C), received vehicle only; (b) group G, received glibenclamide 10 microM L-1; (c) group I, received glibenclamide 10 microM L-1 and 1.4% isoflurane during perfusion; (d) group S, received glibenclamide 10 microM L-1 and 2.7% sevoflurane during perfusion. Glibenclamide was administered 7 min after the start of perfusion. Ten minutes later, the heart was rendered globally ischaemic for 10 min by reducing the preload and afterload to zero, and then the heart was reperfused for 10 min. The formation of hydroxyl radicals in perfusate blood and heart was measured with high performance liquid chromatography using salicylic acid. Hydroxyl radicals react with salicylic acid, yielding dihydroxybenzoic acids. RESULTS: The recovery time from ischaemia in group G was significantly longer than the other groups. However, there were no differences in myocardial metabolites and dihydroxybenzoic acids concentrations in the perfusate and heart among the four groups. CONCLUSIONS: Glibenclamide prolonged recovery time from ischaemia, but did not affect hydroxyl radical formation in the postischaemic reperfused heart. In addition, isoflurane and sevoflurane shortened this time. These facts suggest that mechanisms other than effects of volatile anaesthetics on hydroxyl radical formation are responsible for their protective effects in this model.
Adenosine Triphosphate↗