Minimum alveolar concentration (MAC) of xenon with sevoflurane in humans

BACKGROUND

Although more than 30 yr ago the minimum alveolar concentration (MAC) of xenon was determined to be 71%, that previous study had technological limitations, and no other studies have confirmed the MAC value of xenon since. The current study was designed to confirm the MAC value of xenon in adult surgical patients using more modern techniques.

METHODS

Sixty patients were anesthetized with sevoflurane with or without xenon. They were randomly allocated to one of four groups; patients in group 1 received no xenon, whereas those in groups 2, 3, and 4 received end-tidal concentrations of 20, 40, and 60%, respectively (n = 15 each group). Target end-tidal sevoflurane concentrations were chosen using the "up-and-down" method in each group. After steady state sevoflurane and xenon concentrations were maintained for at least 15 min, each patient was monitored for a somatic response at surgical incision. Somatic response was defined as any purposeful bodily movement. The MAC of sevoflurane and its reduction by xenon was evaluated using the multiple independent variable logistic regression model.

RESULTS

The interaction coefficient of the multiple variable logistic regression was not significantly different from zero (P = 0.143). The MAC of xenon calculated as xenon concentration that would reduce MAC of sevoflurane to 0% was 63.1%.

CONCLUSIONS

The authors could not determine whether interaction in blocking somatic responses in 50% of patients is additive. The MAC of xenon is in the range of the values that were predicted in a previous study.

Effect of heat stress on serotonin-2A receptor-mediated intracellular calcium mobilization in rat C6 glioma cells

This study was conducted to investigate an effect of heat stress at 44 degrees C for 30 min on intracellular Ca2+ signaling system and on heat shock protein (HSP)-70 expression. 5-HT-induced Ca2+ mobilization was reduced 1, 3 and 6 hrs after heat stress, and recovered to the control level 12 and 24 hrs after heat stress. One hr after heat stress, Ca2+ rise was significantly decreased when the cells were stimulated by any concentration of 5-HT. Thrombin-induced Ca2+ increase was also markedly reduced 1 hr after heat stress. HSP-70 level was increased 6 and 9 hr after heat stress. In HSP synthesis inhibitor quercetin-treated cells, HSP-70 expression was not enhanced after heat stress, and Ca2+ rise in response to 5-HT did not return to the control level. However, the Ca2+ rise induced by 5-HT was not restored to the control level after stress in Ac-Asp-Glu-Val-Asp-H (DEVD)-exposed cells while DEVD had little effect on heat stress-induced synthesis of HSP-70. Dexamethasone did not alter the change in HSP-70 expression or Ca2+ response after heat stress. These results indicate that heat stress attenuated 5-HT-induced Ca2+ mobilization and that HSP-70 expression played an important role in recovery from Ca2+ impairment, possibly via protease activity in C6 cells.

[Incidence and severity of coronary artery disease in patients with acute aortic dissection: comparison with abdominal aortic aneurysm and arteriosclerosis obliterans]

OBJECTIVES

The incidence and severity of coronary artery disease were studied in patients with acute aortic dissection (AAD), and compared with coronary artery disease in patients with abdominal aortic aneurysm (AAA) or arteriosclerosis obliterans (ASO).

METHODS

A total of 71 patients(42 males, 29 females, mean age 61.4 +/- 10.0 years) with AAD, undergoing coronary angiography between 1988 and 1999, were studied including 38 patients with open communication type and 33 patients with thrombosed type. According to the Stanford classification, 18 patients were type A and 53 patients were type B. Patients with AAD following Marfan syndrome or chest trauma were excluded from the study. Selective coronary angiography was performed in age- and sex-matched patients with AAA(n = 57; 42 males, 15 females, mean age 63.9 +/- 4.6 years) or ASO (n = 95; 66 males, 29 females, mean age 62.4 +/- 9.4 years). Coronary artery disease was defined as > or = 75% stenosis (left main trunk lesion of > or = 50% stenosis) by multidirectional imaging.

RESULTS

Significant coronary artery disease was demonstrated in 14 patients with AAD (19.7%), 25 patients with AAA (43.9%), and 49 patients with ASO (51.5%). The incidence of coronary artery disease was significantly lower in the AAD group than in the other two groups (p < 0.05). One-vessel disease was present in approximately 70% of the patients with AAD and coronary artery disease. In contrast, multivessel disease was observed in approximately 50% of patients with AAA and ASO. Classification of the patients with AAD according to the blood flow in the false lumen showed coronary artery disease was more highly associated with the thrombosed type [10 (30.3%) of 33 patients] than the open communication type [4 (10.5%) of 38 patients]. Multivariate logistic regression analysis of the patients with AAD showed coronary artery disease was associated with a high serum total cholesterol level (p = 0.025) and the thrombosed type (p = 0.043).

CONCLUSIONS

The incidence of coronary artery disease was significantly lower among patients with AAD than among age- and sex-matched patients with AAA or ASO. Coronary artery disease developed in 30% of the patients with the thrombosed type of AAD, although the prognosis seemed to be good.

A pilot study of paclitaxel and carboplatin for recurrent ovarian cancer

Combination chemotherapy with paclitaxel and platinum is the most effective regimen for advanced ovarian cancer. Second-line chemotherapy with paclitaxel (135 mg/m2, 24 h) and carboplatin (AUC 5-6) is also effective for patients who relapse on the same regimen after 6 months or more. However, it has been shown that the same efficacy and less myelosuppression can be achieved with a 3-h infusion of paclitaxel (135 mg/m2), and that dose intensification of carboplatin to an AUC values larger than 4-6 is meaningless. Therefore, we decided to conduct a pilot study of paclitaxel (135 mg/m2, 3 h) and carboplatin (AUC 4-5) for ovarian cancer patients who had relapsed or were resistant to a platinum-containing regimen without paclitaxel. Eligibility criteria included patients with relapsed or resistant ovarian cancer (no specified duration from prior therapy), age 16-75 years, with performance status 0-2, and adequate bone marrow, renal, and hepatic function. Paclitaxel was administered at a fixed dose of 135 mg/m2 followed by one of two carboplatin doses (AUC 4 or 5). Specific doses were alternated between individual patients by the order in which they entered the study. Treatment was repeated every 3 weeks, and more than 4 cycles were administered. A total of 11 patients were enrolled. Carboplatin was administered to 6 patients at an AUC of 4 and to 5 patients at an AUC of 5. The age of patients ranged from 18 to 65 years (median: 54). Other patient data (number of patients): serous (8), non serous (3), patients with measurable disease (9), assessable/CA 125 (3), study drug administration less than 6 months after prior therapy (5), study drug administration 6 months or more after prior therapy (6). Response was defined by CT and CA 125 level. CR was observed in 25% (2/8), PR in 38% (3/8), NC in 25% (2/8), and PD in 13% (1/8) of the patients. The response rate with assessable patients was 100% (3/3), and the overall response rate was 73% (8/11). Two patients with grade 1 tachycardia and grade 4 thrombocytopenia, respectively, refused further treatment after 2 cycles. No other patients experienced grade 4 hematologic toxicity or grade 3 non-hematologic toxicity. The median survival duration after paclitaxel and carboplatin therapy was 21+ months (6-26+ months). This regimen is easy to manage in heavily pretreated patients and seems to have good efficacy. To further assess the efficacy, a phase II study is needed.

EXAFS study of Sb-Te alloy films

The local structures of three phases; stable compound Sb2Te3, metastable crystalline c-SbTe and amorphous a-SbTe films having the atomic ratio Sb/Te=3: in Sb-Te system have been studied by EXAFS. The c-SbTe has a partly similar local structure to crystalline Sb2Te3. The a-SbTe film has a local structure of NaCl-type, which is topologically analogous to the crystalline form. The amorphous phase has shorter bond distances 2.86A (around Sb-site) and 2.83A (around Te-site) than the corresponding distances 2.89A and 2.87A in the crystalline phase. This unbalanced bond distances between the Sb-site and Te-site implies that site-disordering occurs. Shortening of bond distances in the amorphous phase is due to the relaxation of locally distorted crystalline structure.

Double electron transitions [MN] or [MO] above 74W MIII edge in X-ray absorption spectra

The x-ray absorption spectra in metallic W (Tungsten) have been measured above MIII edge using the third generation synchrotron radiation. ALS, Berkeley. Several features caused by multi-electron transitions were detected on MIII in solid phase. [3p4f], [3p5s], and [3p5p] double electron transitions were identified by the Z+1 approximation.

Multiple hepatic adenomas caused by long-term administration of androgenic steroids for aplastic anemia in association with familial adenomatous polyposis

We report a rare case of hepatic adenomas (HA), in a 20-year-old Japanese girl treated for 6 years with anabolic androgens for aplastic anemia. In a review of the world literature using computer MEDLINE search, we found only 17 cases of androgen-induced HA published between 1975 and 1998 in the English-language literature. The patient was referred to us because of liver lesions detected during a follow-up examination for familial adenomatous polyposis. After being diagnosed with aplastic anemia at 14 years of age, she had been treated with oxymetholone (30 mg/day) for 6 years. Laboratory evaluation revealed normal liver function. Ultrasonography (US) and computed tomography (CT) demonstrated multiple liver lesions. Histopathological examinations of biopsied specimens from the liver tumor showed HA. After the patient was diagnosed with HA, oxymetholone was tapered off. Patients taking androgenic-anabolic steroids should be carefully monitored with US and CT and tumor markers should be measured. This report may be helpful in identifying the population who is at risk of developing hepatic sex hormone-related tumors.

Effect of acute lipopolysaccharide administration on (+/-)-1-(2,5-dimethoxy-4-iodophenyl)-2 aminopropane-induced wet dog shake behavior in rats: comparison with body weight change and locomotor activity

1. Several reports have shown that serotonin (5-HT)2A receptor density and its function are altered after physiological or pharmacological stress. To examine whether an acute administration of lipopolysaccharide (LPS), a bacterial endotoxin, affected 5-HT2A receptor function, wet dog shakes of male Wistar rats were observed after a subcutaneous injection of DOI, a 5-HT2A receptor agonist following LPS treatment. Body weight change and locomotor activity were also observed. 2. DOI (1 mg/kg)-induced WDS significantly decreased after 400 or 1000 microg/kg LPS treatment compared with that of control rats 1 and 3 hr after injection, and WDS completely recovered 8 hr after LPS treatment. Treatment with 10 mg/kg indomethacin (IND) or 1 mg/kg naltrexone (NLTX) canceled the effect of 400 microg/kg LPS on DOI-induced WDS. 3. Body weight decrease was significantly greater in LPS-treated rats compared with control rats 3, 5 and 8 hr after treatment. Treatment with IND (10 mg/kg) significantly recovered the reduction in body weight induced by 400 microg/kg LPS. Treatment with NLTX (1 mg/kg) also prevented the LPS effect on body weight decrease. 4. Eight hr after treatment with LPS (400 microg/kg), the rats showed significant attenuation of locomotor activity. IND (10 mg/kg) treatment abolished the inhibitory effect of LPS on locomotor activity, and NLTX (1 mg/kg) also improved the decrease in locomotion 8 hr after LPS treatment. 5. Plasma tumor necrosis factor (TNF)-alpha concentration dramatically increased 1 hr after the injection of 400 microg/kg LPS, and returned almost to the basal level 3 hr later. Next, rats were injected with 50 microg/kg TNF-alpha intraperitoneally, and body weight change and DOI-induced WDS was determined 3 hr after TNF-alpha injection. Body weight loss was significantly greater in rats treated with TNF-alpha. On the other hand, DOI-induced WDS was not altered when rats were treated with TNF-alpha. 6. These results suggest that acute treatment with LPS inhibited 5-HT2A receptor-mediated behavior via cyclooxygenase and opioid receptor activation, but that the inhibition of the WDS by LPS appears to be independent of TNF-alpha production.

ST segment elevation in the right precordial leads following administration of class Ic antiarrhythmic drugs

Electrocardiographic changes were evaluated retrospectively in five patients without previous episodes of syncope or ventricular fibrillation who developed abnormal ST segment elevation mimicking the Brugada syndrome in leads V1-V3 after the administration of class Ic antiarrhythmic drugs. Pilsicainide (four patients) or flecainide (one patient) were administered orally for the treatment of symptomatic paroxysmal atrial fibrillation or premature atrial contractions. The QRS duration, QTc, and JT intervals on 12 lead surface ECG before administration of these drugs were all within normal range. After administration of the drugs, coved-type ST segment elevation in the right precordial leads was observed with mild QRS prolongation, but there were no apparent changes in JT intervals. No serious arrhythmias were observed during the follow up periods. Since ST segment elevation with mild QRS prolongation was observed with both pilsicainide and flecainide, strong sodium channel blocking effects in the depolarisation may have been the main factors responsible for the ECG changes. As the relation between ST segment elevation and the incidence of serious arrhythmias has not yet been sufficiently clarified, electrocardiographic changes should be closely monitored whenever class Ic drugs are given.

Triangulation and adolescent development in the U.S. and Japan

Using an indirect measure of family structure, relationships between parents and adolescents were studied in 99 U. S. and 60 Japanese families. As two-person relationships tend toward instability under stress, a third person may be drawn in to stabilize the system. Parents, for example, may avoid the tension in the marital relationship by focusing together on an adolescent's problem, or pull the adolescent into a coalition with one parent. Either way the parents are said to have "triangled" the adolescent. In this study, a relationship is found between parents avoiding tension in their own relationship and their tendency to triangle an adolescent. Triangled daughters, in both cultures, had lower scores on ego development, supporting the hypothesis that such patterns can be detrimental to the adolescent's personal development. The discussion includes comments on cross-cultural research.

Does an early increase in heart rate during tilting predict the results of passive tilt testing?

Head-up tilt testing is a useful but time-consuming procedure. If we could accurately predict the tilt testing results; we would be able to substantially shorten the duration of tilt protocol. To clarify the hypothesis that an early increase in heart rate (HR) during tilting can predict the passive tilt results in our protocol (80-degree angle for 30 minutes), we studied 115 consecutive patients (72 men, 43 women, mean age 46 +/- 19 years) who were clinically diagnosed with neurally mediated syncope. Twenty-nine (25%) patients had a positive tilt test (P group), whereas 86 (75%) patients had a negative test (N group). The early HR increase was defined as the maximum HR during the first 5 minutes of tilting minus the resting HR before tilting. The early HR increase was significantly higher in the P group (23.8 +/- 9.5 beats/min) than in the N group (17.5 +/- 8.2 beats/min, P = 0.0008), but it was negatively correlated with the tilt duration to positive response (r = -0.52, P = 0.0032) and the patient age in the entire study population (r = 0.62, P < 0.0001). Results of multiple regression analysis indicated that age, tilt result, and tilt duration were independently associated with the early HR increase. As a result, an early HR increase > or = 18 beats/min, the best apparent cut-off point obtained in our study, was a sensitive (100%) marker for prediction of a positive response at < or = 15 minutes of tilting, but it showed a low specificity (61%). In conclusion, an early HR increase during 80-degree tilting may be only predictive for a positive result < or = 15 minutes because it depends on the tilt duration to a positive response and patient age.

Minimum alveolar concentration-awake of Xenon alone and in combination with isoflurane or sevoflurane

BACKGROUND

The minimum alveolar concentration (MAC)-awake is a traditional index of hypnotic potency of an inhalational anesthetic. The MAC-awake of xenon, an inert gas with anesthetic properties (MAC = 71%), has not been determined. It is also unknown how xenon interacts with isoflurane or sevoflurane on the MAC-awake.

METHODS

In the first part of the study, 90 female patients received xenon, nitrous oxide (N2O), isoflurane, or sevoflurane supplemented with epidural anesthesia (n = 36 for xenon and n = 18 per group for other anesthetics). In the second part, 72 additional patients received either xenon or N2O combined with the 0.5 times MAC-awake concentration of isoflurane or sevoflurane (0.2% and 0.3%, respectively, based on the results of the first part; n = 18 per group). During emergence, the concentration of an assigned anesthetic (xenon or N2O only in the second part) was decreased in 0. 1 MAC decrements every 15 min from 0.8 MAC or from 70% in the case of N2O until the patient followed the command to either open her eyes or to squeeze and release the investigator's hand. The concentration midway between the value permitting the first response to command and that just preventing it was defined as the MAC-awake.

RESULTS

The MAC-awake were as follows: xenon, 32.6 +/- 6.1% (mean +/- SD) or 0.46 +/- 0.09 MAC; N2O, 63.3 +/- 7.1% (0.61 +/- 0.07 MAC); isoflurane, 0.40 +/- 0.07% (0.35 +/- 0.06 MAC); and sevoflurane, 0.59 +/- 0.10% (0.35 +/- 0.06 MAC). Addition of the 0.5 MAC-awake concentrations of isoflurane and sevoflurane reduced the MAC-awake of xenon to 0.50 +/- 0.15 and 0.51 +/- 0.16 times its MAC-awake as a sole agent, but that of N2O to the values significantly greater than 0.5 times its MAC-awake as a sole agent (0.68 +/- 0.12 and 0.66 +/- 0.14 times MAC-awake; P < 0.01, analysis of variance and Dunnett's test).

CONCLUSIONS

The MAC-awake of xenon is 33% or 0.46 times its MAC. In terms of the MAC-fraction, this is smaller than that for N2O but greater than those for isoflurane and sevoflurane. Unlike N2O, xenon interacts additively with isoflurane and sevoflurane on MAC-awake.

Structure and biological activities of eumenine mastoparan-AF (EMP-AF), a new mast cell degranulating peptide in the venom of the solitary wasp (Anterhynchium flavomarginatum micado)

A new mast cell degranulating peptide, eumenine mastoparan-AF (EMP-AF), was isolated from the venom of the solitary wasp Anterhynchium flavomarginatum micado, the most common eumenine wasp found in Japan. The structure was analyzed by FAB-MS/MS together with Edman degradation, which was corroborated by solid-phase synthesis. The sequence of EMP-AF, Ile-Asn-Leu-Leu-Lys-Ile-Ala-Lys-Gly-Ile-Ile-Lys-Ser-Leu-NH(2), was similar to that of mastoparan, a mast cell degranulating peptide from a hornet venom; tetradecapeptide with C-terminus amidated and rich in hydrophobic and basic amino acids. In fact, EMP-AF exhibited similar activity to mastoparan in stimulating degranulation from rat peritoneal mast cells and RBL-2H3 cells. It also showed significant hemolytic activity in human erythrocytes. Therefore, this is the first example that a mast cell degranulating peptide is found in the solitary wasp venom. Besides the degranulation and hemolytic activity, EMP-AF also affects on neuromuscular transmission in the lobster walking leg preparation. Three analogs EMP-AF-1 approximately 3 were snythesized and biologically tested together with EMP-AF, resulting in the importance of the C-terminal amide structure for biological activities.

Pattern electroretinogram elicited by a dartboard pattern

The receptive field size of retinal ganglion cells is closely related to their eccentricity from the fovea. To elicit larger pattern-reversal electroretinograms (P-ERGs), it may be useful to stimulate the retina with patterns having elements that parallel this change in receptive field size. We describe a dartboard pattern consisting of reversal elements that enlarge gradually from the central to the peripheral stimulus field. The utility of the dartboard pattern for eliciting P-ERG was investigated by comparing it with the conventional uniform checkerboard pattern, but with the other stimulus parameters remaining unchanged (96% contrast, 35.9 cd/m2 mean luminance, 3.3 rev/s temporal frequency, 15 degrees circular field). The dartboard pattern produced a significantly larger P50 amplitude than did the checkerboard pattern, while no difference in peak latency was found when 54 min of arc was used as a standard check size for the checkerboard pattern. The dartboard pattern for eliciting P-ERG should prove clinically useful.

Circadian variation of vasovagal syncope

INTRODUCTION

Circadian patterns have been demonstrated for several cardiovascular catastrophes. Chronobiologic factors play a role in the emergence of vasovagal syncope (VVS); however, diurnal variation of syncopal episodes in VVS has not been reported previously.

METHODS AND RESULTS

We assessed daily distribution of the time of syncopal episodes in VVS. Time of syncope could be determined in 80 episodes in 54 patients (32 men and 22 women; mean age 37 years, range 12 to 67). Patients who were prescribed beta blockers or vasodilators, and who had syncopes related to alcohol intake, were excluded from the study. Head-up tilt testing was performed in 53 patients. The distribution of the episodes of VVS in 3-hour intervals differed significantly from uniform occurrence (P < 0.0001), with a peak frequency between 6 A.M. and noon (67.5% of total episodes). In patients who had experienced the initial syncope in the morning, most (78%) of the next syncopal episodes also occurred in the morning. There was no significant correlation between the time of last syncopes and tilt testing results.

CONCLUSION

We demonstrated a prominent circadian variation in the frequency of VVS, with a peak in the morning. Recognition of the daily distribution of VVS is useful for patient education and therapeutic strategy.

Emergence agitation after sevoflurane versus propofol in pediatric patients

Sevoflurane may be associated with a high incidence of emergence agitation in preschool children. We tested the hypothesis that maintenance of anesthesia with propofol after sevoflurane induction would reduce the incidence of this excitatory behavior compared with continuing sevoflurane for maintenance. We conducted a randomized, single-blinded, two-period, cross-over study in 16 preschool age children undergoing repeated brief general anesthetics for eye examination. After sevoflurane induction, patients were randomly assigned to receive either sevoflurane or propofol anesthesia for maintenance. The alternative anesthetic was used for the maintenance of anesthesia on the second occasion. We compared the speed and quality of recovery characteristics of these anesthetics, as well as, overall parent satisfaction with anesthesia. Eight patients first received sevoflurane and the remaining eight patients first received propofol. Of the patients who received sevoflurane for the maintenance of anesthesia, 38% developed emergence agitation. In contrast, none developed emergence agitation when propofol was administered for maintenance of anesthesia. Despite emergence agitation, sevoflurane provided a shorter postanesthesia care unit stay than propofol. Parent satisfaction with anesthesia was greater with propofol than with sevoflurane.

IMPLICATIONS

In this cross-over study, we observed the incidence of emergence agitation with sevoflurane (38%) was significantly greater than with propofol (0%) in premedicated, preschool-aged children undergoing minor noninvasive surgery.

The personal identification of many samples recovered from under the sea

An automatic and rapid DNA typing system was employed for personal identification, using fragmentary tissue samples from victims in an airplane accident. Two victims were crushed into small pieces, and 33 samples suspected to belong to them were recovered from under the sea. From each sample, 10 mg was used for testing. The parents' bloods of two presumptive victims were also examined. DNA extraction from samples was performed by the NaI method, and the obtained DNA samples were analyzed with the ABI PRISM system. Among 33 samples, 31 samples were identified to be human tissues, possibly from two victims. The other two samples seemed to be parts of marine animals. ABO blood group, STR polymorphism, and mitochondrial DNA polymorphism typing were possible in every examined human sample. Two victims' fragmentary tissues were identified by determining ABO genotype, STR type and mitochondrial DNA type. The system we employed enabled an accurate typing of many fragmentary samples in a short time, thus contributing to the fast and secure identification of many victims in such cases as big air accidents.

Bispectral analysis of the electroencephalogram does not predict responsiveness to verbal command in patients emerging from xenon anaesthesia

The bispectral index (BIS) is derived empirically from the electroencephalogram database of patients receiving common anaesthetics, but it may not be valid for uncommon agents. Therefore, we investigated how xenon affects the BIS. Nine and 11 patients were anaesthetized with 0.8 of the minimal alveolar concentration (MAC) of isoflurane (0.92%) and xenon (56%), respectively. After the end of operation, these concentrations were decreased in decrements of 0.1 MAC (isoflurane 0.12% or xenon 7%) and each new concentration was maintained for 15 min. This was repeated until the patient first opened her eyes or squeezed the investigator's hand on command. Isoflurane and xenon at 0.8 MAC reduced the BIS to a median of 40 (range 36-53) and 36 (30-61), respectively. With decreasing concentrations of isoflurane, the BIS increased progressively and it reached a median of 96 (90-98) when the patients awoke. In contrast, four patients receiving xenon responded to verbal command while the BIS was below 50 [median 45 (range 41-49)]. The remaining seven patients in the xenon group awoke when their BIS was greater than 80 [median 96 (range 82-98)], but in four of them the BIS was no greater than 50 when the xenon concentration was only 0.1 MAC (7%) higher than that associated with awakening. We conclude that low BIS values (< 50) do not guarantee adequate hypnosis during xenon anaesthesia.

Emergence agitation after sevoflurane versus propofol in pediatric patients

Sevoflurane may be associated with a high incidence of emergence agitation in preschool children. We tested the hypothesis that maintenance of anesthesia with propofol after sevoflurane induction would reduce the incidence of this excitatory behavior compared with continuing sevoflurane for maintenance. We conducted a randomized, single-blinded, two-period, cross-over study in 16 preschool age children undergoing repeated brief general anesthetics for eye examination. After sevoflurane induction, patients were randomly assigned to receive either sevoflurane or propofol anesthesia for maintenance. The alternative anesthetic was used for the maintenance of anesthesia on the second occasion. We compared the speed and quality of recovery characteristics of these anesthetics, as well as, overall parent satisfaction with anesthesia. Eight patients first received sevoflurane and the remaining eight patients first received propofol. Of the patients who received sevoflurane for the maintenance of anesthesia, 38% developed emergence agitation. In contrast, none developed emergence agitation when propofol was administered for maintenance of anesthesia. Despite emergence agitation, sevoflurane provided a shorter postanesthesia care unit stay than propofol. Parent satisfaction with anesthesia was greater with propofol than with sevoflurane.

IMPLICATIONS

In this cross-over study, we observed the incidence of emergence agitation with sevoflurane (38%) was significantly greater than with propofol (0%) in premedicated, preschool-aged children undergoing minor noninvasive surgery.

Effect of probucol on repeat revascularization rate after percutaneous transluminal coronary angioplasty (from the Probucol Angioplasty Restenosis Trial [PART])

To address the issue of whether probucol reduces clinical events after percutaneous transluminal coronary angioplasty (PTCA), we surveyed clinical status at 1 year after PTCA of 101 patients who had entered the Probucol Restenosis Angioplasty Trial. Repeat angioplasty at index lesions were required in 5 patients in the probucol group and in 12 in the control group, suggesting that probucol administered beginning 4 weeks before PTCA reduces repeat revascularization rates for 1 year.

Extracellular ATP triggers tumor necrosis factor-alpha release from rat microglia

Brain microglia are a major source of inflammatory cytokines, such as tumor necrosis factor-alpha (TNF-alpha), which have been implicated in the progression of neurodegenerative diseases. Recently, microglia were revealed to be highly responsive to ATP, which is released from nerve terminals, activated immune cells, or damaged cells. It is not clear, however, whether released ATP can regulate TNF-alpha secretion from microglia. Here we demonstrate that ATP potently stimulates TNF-alpha release, resulting from TNF-alpha mRNA expression in rat cultured brain microglia. The TNF-alpha release was maximally elicited by 1 mM ATP and also induced by a P2X(7) receptor-selective agonist, 2'- and 3'-O-(4-benzoylbenzoyl)adenosine 5'-triphosphate, suggesting the involvement of P2X(7) receptor. ATP-induced TNF-alpha release was Ca(2+)-dependent, and a sustained Ca(2+) influx correlated with the TNF-alpha release in ATP-stimulated microglia. ATP-induced TNF-alpha release was inhibited by PD 098059, an inhibitor of extracellular signal-regulated protein kinase (ERK) kinase 1 (MEK1), which activates ERK, and also by SB 203580, an inhibitor of p38 mitogen-activated protein kinase. ATP rapidly activated both ERK and p38 even in the absence of extracellular Ca(2+). These results indicate that extracellular ATP triggers TNF-alpha release in rat microglia via a P2 receptor, likely to be the P2X(7) subtype, by a mechanism that is dependent on both the sustained Ca(2+) influx and ERK/p38 cascade, regulated independently of Ca(2+) influx.

Successful radiofrequency catheter ablation of left ventricular tachycardia following surgical correction of tetralogy of Fallot

A 13-year-old boy had recurrent ventricular tachycardia following surgical correction of tetralogy of Fallot. Pharmacological management with multiple antiarrhythmic drugs failed, and the patient underwent electrophysiological evaluation. A reentrant tachycardia involving a slowly conducting region in the left ventricular outflow tract was demonstrated. We performed radiofrequency catheter ablation after identifying the essential components of the reentrant circuit. The ventricular tachycardia could no longer be induced and did not recur spontaneously during a 13-month follow-up.