Development of enzyme-linked immunosorbent assay for human cardiac myosin light chain I

We have developed a new enzyme-linked immunosorbent assay (ELISA) for the determination of cardiac myosin light chain I (MLI) in human serum. The detection range of ELISA was between 1 and 50 ng/ml, and serial dilutions of human serum showed good linearity. The recovery of different concentrations of cardiac MLI ranged from 87.5% to 100.0%. The intra-assay (n=5) and inter-assay (n=5) showed good results (C.V.<10%). The cross-reactivity with skeletal-myosin light chain (ML) was rather high, but was negligible with other myosin light chains. The concentrations of cardiac MLI in human serum determined by ELISA were similar to those determined by immunoradiometric assay (IRMA). The total assay time and sample volume required for ELISA were approx. 2 h and 25 microl, respectively, while those for IRMA are approx. 24 h and 100 microl. Our novel ELISA method therefore has significant advantages for clinical analysis.

Effects of propofol and thiopental on the central nervous system during nociceptive stimulation in cats

PURPOSE

Nociceptive stimulation may increase central nervous system (CNS) activity during anesthesia. However, it is not known whether propofol and thiopental have a similar inhibitory effect on the CNS during nociceptive stimulation. Therefore, we compared the antinociceptive effects of propofol and thiopental in cats.

METHODS

In 12 cats, anesthesia was induced with 4% halothane in oxygen and maintained with 0.5% halothane in oxygen. The cortical electroencephalogram (EEG) and the electrical activity from the midbrain reticular neurons (R-MUA) were measured before and after sciatic nerve stimulation. The cats were then allocated to receive cumulative doses of either propofol (n = 6) or thiopental (n = 6) i.v. at 5-min intervals. Two minutes after each dose, the cortical EEG and the R-MUA were compared before and after sciatic nerve stimulation.

RESULTS

Propofol and thiopental depressed the basal R-MUA to a similar degree at each dose. Sciatic nerve stimulation increased the R-MUA, and there were no differences in the maximum R-MUA values between propofol and thiopental. The cortical EEGs after each dose of anesthetic without stimulation showed similar patterns, and the patterns of change with stimulation were also similar for these two anesthetics.

CONCLUSION

Propofol and thiopental have similar antinociceptive effects in cats.

[Primary cardiac malignant lymphoma diagnosed intraoperatively during aortic valve repair; report of a case]

A 58-year-old male who complained of chest oppression on effort was diagnosed as aortic regurgitation by echocardiography. The cardiac catheterization was showed moderate aortic regurgitation. He was referred to our hospital for aortic valve replacement. We considered preoperatively that the aortic regurgitation is due to infective endocarditis or aortitis syndrome. We have not noticed cardiac tumor at all until aortic valve replacement. Postoperative pathological diagnosis of the tumor was malignant lymphoma. The tumor had a characteristic architecture of a cardiac MICE (mesothelial/monocytic incidental cardiac excrescence). After the operation, additional chemotherapy using doxorubicin and cysplatin was performed. The patient has been doing well for 5 years after operation.

Interaction of thyroid-stimulating antibody with Graves' thyroid-stimulating hormone-binding antibody

OBJECTIVE

Evidence of anti-thyroid-stimulating hormone (TSH) antibody in Graves' serum has been reported. We found that extremely high Graves' anti-TSH antibodies neutralized other Graves' thyroid-stimulating antibody (TSAb) activity.

METHOD

TSAb-IgG was affinity-purified by Sepharose-bound Graves' anti-TSH antibody (extremely high).

RESULT

The thyroid-stimulating activity in affinity-purified TSAb-IgG increased about 4-5 times compared to that before purification. TSH-binding inhibitory immunoglobulin (TBII) activity in affinity-purified TSAb-IgG also increased using TSH receptor-coated tube assay. A similar increase of thyroid-stimulating activity accompanied with TBII activity was also observed in affinity-purified TSAb-IgG-F(ab')(2).

CONCLUSION

This suggests the possibility that either TSAb may be an anti-idiotypic antibody against anti-TSH antibody or anti-TSH antibody may be an anti-idiotypic antibody against anti-TSH receptor antibody.

Inhibitory effect of propofol on ketamine-induced c-Fos expression in the rat posterior cingulate and retrosplenial cortices is mediated by GABAA receptor activation

BACKGROUND

Non-competitive N-methyl-D-aspartate (NMDA) receptor antagonists, including ketamine, have psychotomimetic activities and cause neuronal damage in the posterior cingulate and retrosplenial cortices (PC/RS), which are suggested to be the brain regions responsible for their psychotomimetic activities. We previously demonstrated that ketamine induced marked c-Fos (c-fos protein) expression in the rat PC/RS, which was inhibited by propofol, and the expression was closely related to ketamine-induced abnormal behavior. In the present study, we investigated whether the inhibition by propofol was mediated by GABAA receptor receptor activation.

METHODS

Using Wistar rats, propofol alone, propofol with bicuculline or propofol with flumazenil was injected intravenously and then continuously infused. Fifteen minutes later, 100 mg kg-1 of ketamine or normal saline was injected intraperitoneally. Two hours after the ketamine or saline injection, the brain was extracted and brain sections were prepared, and c-Fos expression was detected using immunohistochemical methods.

RESULTS

Ketamine induced marked c-Fos expression in the PC/RS (171 +/- 9/0.4 mm2), which was significantly inhibited by propofol (5 +/- 5/0.4 mm2). The inhibition by propofol was disinhibited dose-dependently by both bicuculline (0.5 and 1.0 mg kg-1 bicuculline groups: 46 +/- 15 and 143 +/- 16, respectively) and flumazenil (0.1 and 1.0 mg kg-1 flumazenil groups: 79 +/- 6 and 130 +/- 15, respectively).

CONCLUSION

These results demonstrate that the inhibitory effect of propofol on ketamine-induced c-Fos expression in the PC/RS is mediated by GABAA receptor activation, and suggests that ketamine-induced psychoneuronal adverse effects may be suppressed by propofol via the activation of GABAA receptors.

The clinical significance of colonoscopy in hemorrhagic colitis due to enterohemorrhagic Escherichia coli O157:H7 infection

BACKGROUND AND STUDY AIMS

Although hemorrhagic colitis due to enterohemorrhagic Escherichia coli O157:H7 (O157) infection has recently attracted increasing attention as an important enteric infection, the colonoscopic findings associated with this disease have not been sufficiently characterized. The aim of this study is to characterize the colonoscopic features of hemorrhagic colitis due to O157 infection.

PATIENTS AND METHODS

The colonoscopic findings in ten patients with hemorrhagic colitis due to O157 infection were retrospectively reviewed. To assess the severity of inflammation in each part of the large intestine, colonoscopic findings were categorized into four grades: grade 1, intact mucosa; grade 2, sporadic erythema and erosion; grade 3, mostly diffuse inflammation; and grade 4, diffuse, severe inflammation.

RESULTS

Eight out of ten patients had grade 4 findings in the cecum and ascending colon, grade 3 in the transverse colon and descending colon, and grade 2 in the sigmoid colon. Two of these eight patients also had grade 4 inflammation in the proximal transverse colon. Five of these eight patients revealed longitudinal ulcer-like lesions in the transverse colon and/or descending colon. The remaining two patients had grade 3 findings in the cecum to the descending colon and grade 2 findings in the sigmoid colon. All patients exhibited grade 1 finding in the terminal ileum and the rectum. Based on these colonoscopic findings, the ten patients were divided into the typical group (eight patients) and the mild-type group (two patients).

CONCLUSIONS

The characteristic colonoscopic findings in most patients with hemorrhagic colitis due to O157 infection were as follows: 1) severe inflammation, including primarily marked edema and facile hemorrhage, and 2) inflammation predominating at the right-side colon; and 3) frequent appearance of longitudinal ulcer-like lesions.

Characterizations of recombinant human tartrate-resistant acid phosphatase from osteosarcoma: comparison study between recombinant and placental proteins

We cloned the human tartrate-resistant acid phosphatase (TRAP) gene from human osteosarcoma cells (Saos-2), and produced recombinant human TRAP (rhTRAP) using a baculovirus vector expression system. RhTRAP from Sf9 culture medium was purified by cation exchange chromatography, gel filtration and affinity chromatography. The molecular mass and amino acid composition of the rhTRAP were consistent with the deduced amino acid composition from the TRAP gene. The N-terminal amino acid sequence of rhTRAP was identical to that of TRAP purified from osteoclastoma and hairy cell leukemia spleen. The monoclonal antibodies generated against rhTRAP also reacted to human placental TRAP (pTRAP). The optimum pH of rhTRAP and pTRAP were pH 5.0-5.5 and pH 6.0-6.5, respectively. The enzymatic activities of rhTRAP and pTRAP were activated by reducing agents such as 2-mercaptoethanol, dithiothreitol and ascorbic acid. The activities of rhTRAP and pTRAP were enhanced by Fe2+ ions, but were inhibited by Fe3+ ions. The present results indicate that rhTRAP has similar properties to the native human TRAP, and suggest that the enhancement of TRAP activity by reducing agents might be expressed via the reduction of Fe ions at the metal center.

A useful ELISA system for human liver-type arginase, and its utility in diagnosis of liver diseases

OBJECTIVES

To develop a new ELISA system for liver-type arginase using monoclonal antibodies against the enzyme, and to verify the utility of the arginase in diagnosis of hepatic disorders.

DESIGN AND METHODS

We have developed an enzyme-linked immunosorbent assay (ELISA), using two kinds of monoclonal antibodies (Mo6G3 and Mo9C5) for human liver-type arginase as the first and second antibodies respectively. We have also developed a new method to eliminate the influence of erythrocyte-derived arginase contamination in hemolytic samples. This ELISA was applied to specimens received from patients with acute and chronic hepatic disease and also patients who had undergone partial hepatectomy.

RESULTS

This assay is sensitive and reproducible for the measurement of liver-type arginase in the sera of patients with liver dysfunction, and enabled us to detect enzyme concentrations as low as 27 pmol/L without any processing of the samples. The assay showed within-run coefficients of variation (CV) ranging from 1.9 to 4.1% and between-day CV from 3.6 to 5.1% for arginase concentrations varying from 57.1 to 1200 pmol/L. The recovery was 113% (mean) with a range of 96 to 129%. These antibodies reacted strongly with both recombinant and native liver-type arginases, while, to some extent, with erythrocyte-derived arginase. Correction for erythrocyte-derived arginase contamination in hemolytic samples was, however, easily made by assaying peroxidase-like activity of hemoglobin. From the view of a limited localization of arginase in the liver, the marked increase of the enzyme in serum reflects initiation of liver injury, while the rapid decrease reflects termination of the damage. Such quick normalization in circulating liver-type arginase indicated another merit of the enzyme in diagnosis of liver diseases.

CONCLUSIONS

The changes in circulating liver-type arginase level could be helpful not only in the diagnosis of liver diseases but also subsequent treatment of the patients with liver damage.

TSBAb (TSH-stimulation blocking antibody) and TSAb (thyroid stimulating antibody) in TSBAb-positive patients with hypothyroidism and Graves' patients with hyperthyroidism

There are two types of TSH receptor antibodies (TRAb); thyroid stimulating antibody (TSAb) and TSH-stimulation blocking antibody (TSBAb). TSAb causes Graves' hyperthyroidism. TSBAb causes hypothyroidism. Both TSAb and TSBAb block TSH-binding to thyroid cells as TSH receptor antibodies (TRAb). TSBAb-positive patients with hypothyroidism and Graves' patients with hyperthyroidism may have both TSBAb and TSAb. We studied TSBAb and TSAb in 43 TSBAb-positive patients with hypothyroidism and in 55 untreated Graves' patients with hyperthyroidism. TSBAb-activities were expressed as percentage inhibition of bovine (b) TSH-stimulated cAMP production by test IgG. Two formulas were used to calculate TSBAb-activities; TSBAb-A (%) = [1 - (c - b)/(a - b)] x 100 and TSBAb-B (%) = [1 - (c - d)/(a - b)] x 100, where a: cAMP generated in the presence of normal IgG and bTSH, b: cAMP generated in the presence of normal IgG, c: cAMP generated in the presence of test IgG and bTSH, and d: cAMP generated in the presence of test IgG. TSAb (%) = [d/b] x 100. All of the 43 TSBAb-positive patients with hypothyroidism had strongly positive TSBAb-A and -B. Some of them had weakly positive TSAb (<240%). All 55 untreated Graves' patients had positive TSAb (205-2509%). Some of them had both TSAb and TSBAb. TSBAb-positive patients with hypothyroidism had a limited distribution of TSBAb- and TSAb-activities (TSBAb-A + 75 - + 103%, TSBAb-B + 87 - + 106%, TSAb 92-240%), but Graves' patients with hyperthyroidsim had a wide distribution of TSAb- and TSBAb-activities (TSAb 205-2509%, TSBAb-A - 158 - + 43%, TSBAb-B - 14 - + 164%). TSBAb-A ignores TSAb activity in serum, and might give low TSBAb activity. However, TSBAb-A clearly differentiates TSBAb-positive patients with hypothyroidism from Graves' patients with hyperthyroidism; thus, we favor TSBAb-A over TSBAb-B. Some of TSBAb-positive patients with hypothyroidism and Graves' patients with hyperthyroidism have both TSBAb and TSAb.

Xenon inhibits but N(2)O enhances ketamine-induced c-Fos expression in the rat posterior cingulate and retrosplenial cortices

Both nitrous oxide (N(2)O) and xenon are N:-methyl-D-aspartate receptor antagonists that have psychotomimetic effects and cause neuronal injuries in the posterior cingulate and retrosplenial cortices. We investigated the effect of xenon, xenon with ketamine, N(2)O, and N(2)O with ketamine on c-Fos expression in the rat posterior cingulate and retrosplenial cortices, a marker of psychotomimetic effects. Brain sections were prepared, and c-Fos expression was detected with immunohistochemical methods. A loss of microtubule-associated protein 2, a marker of neuronal injury, was also investigated. The number of Fos-like immunoreactivity positive cells by ketamine IV at a dose of 5 mg/kg under 70% N(2)O (128 +/- 12 cells per 0.5 mm(2)) was significantly more than those under 30% (15 +/- 2 cells per 0.5 mm(2)) and 70% xenon (2 +/- 1 cells per 0.5 mm(2)). Despite differences in c-fos immunoreactivity, there was no loss of microtubule-associated protein 2 immunoreactivity in any group examined. Xenon may suppress the adverse neuronal effects of ketamine, and combined use of xenon and ketamine seems to be safe in respect to neuronal adverse effects.

Sensitive assay to detect thyroid stimulating antibody (TSAb) in the presence of thyroid stimulation blocking antibody (TSBAb) in serum

The detection of thyroid stimulating antibody (TSAb) activity in the presence of thyroid stimulation blocking antibody (TSBAb) in Graves' serum is difficult because TSBAb blocks TSAb activity. We recently demonstrated that polyethylene glycol (PEG) augments TSAb activity in porcine thyroid cells (PTC) assay. This PEG-induced augmentation makes it possible to develop a sensitive assay to detect TSAb in the presence of TSBAb. We studied the effects of PEG on TSAb- and TSBAb-activities in PTC using 4 different preparations of the samples; (1) crude IgG using PEG 22.5% precipitated fraction (PF) from Graves' serum (0.2 ml), (2) crude IgG using PEG 12.5% PF, (3) serum (50 microl), and (4) serum (50 microl) in the presence of 5% PEG (final). When the effects of PEG on TSAb activity using crude IgG were examined, PEG 22.5% PF showed significantly higher TSAb activity than PEG 12.5% PF as reported previously. The augmentative effect of PEG on TSAb activity was also observed by the addition of 5% PEG to serum. We also demonstrated that PEG augmented TSAb-activities even in TSBAb-positive serum by two methods (crude IgG using PEG 22.5% PF and the addition of 5% PEG to serum). TSBAb activities were expressed by two calculation methods (A= [1 - (a - b)/(c - d) x 100] and B = [1 - (a - d)/(c - d) x 100], where a is cAMP produced in the presence of bTSH and patient's IgG, b is cAMP produced in the presence of patient's IgG, c is cAMP produced in the presence of bTSH and normal IgG, and d is cAMP produced in the presence of normal IgG). In the presence of TSAb, the values of A method were always higher than those of B method, since TSAb stimulated cAMP synthesis. We have developed two sensitive methods to detect TSAb even in the presence of TSBAb in serum using PEG; 1) incubation of crude IgG using PEG 22.5% PF from serum (0.2 ml), and 2) co-incubation of 5 % PEG with test serum (50 microl).

Effects of sustained low-flow ischemia and reperfusion on Ca2+ transients and contractility in perfused rat hearts

We investigated changes in cytoplasmic Ca2+ concentration ([Ca2+]i) and in left ventricular contractility during sustained ischemia and reperfusion in isolated beating rat hearts. Hearts from male Sprague-Dawley rats were perfused retrogradely and were loaded with 4 microM fura-2. Low-flow global ischemia was induced by reducing perfusion flow to 10% and by electric pacing. The hearts were exposed to ischemia for 10 min or 30 min and then reperfused. [Ca2+]i was measured by monitoring the ratio of 500 nm fluorescence excited at 340 and 380 nm while simultaneously measuring left ventricular pressure (LVP). To determine diastolic [Ca2+]i, background autofluorescence was subtracted. LVP rapidly decreased from 82.3+/-8.2 to 17.1+/-2.9 mmHg , whereas the amplitude of the Ca2+ transient did not change significantly during the first 1 min of ischemia. After 10 min of ischemia, the amplitude decreased to 60.8+/-10.6% (p < 0.05) and diastolic [Ca2+]i increased by 26.3+/-2.9% (p < 0.001) compared with the pre-ischemic value (n = 8). When the hearts were reperfused after 10 min of ischemia, the amplitude of the Ca2+ transient and LVP recovered to 79.0+/-7.2% and 73.2+/-7.5 mmHg, respectively. Whereas diastolic [Ca2+]i decreased to the preischemic value. In the hearts exposed to 30 min of ischemia (n = 10), diastolic [Ca2+]i increased even further by 32.7+/-5.3% at the end of ischemia and continued increasing during the 10 min of reperfusion by 42.6+/-15.6%. Six of 10 hearts developed ventricular fibrillation (VF) and intracellular Ca2+ overload after reperfusion. Recovery of LVP after reperfusion was significantly smaller in the hearts exposed to 30 min of ischemia than in the hearts exposed to 10 min of ischemia (58.9+/-11.7 vs. 97.2+/-3.0% of pre-ischemic value, p < 0.05). Diastolic [Ca2+]i also increased under hypoxic conditions (N2 bubbling) in this model. These results suggest that increases in diastolic [Ca2+]i might play an important role in myocardial contractile dysfunction and viability in ischemia-reperfusion injury.

Remission of Graves' hyperthyroidism predicted by smooth decreases of thyroid-stimulating antibody and thyrotropin-binding inhibitor immunoglobulin during antithyroid drug treatment

It is important to know whether a patient with Graves' disease will get into remission or not during antithyroid drug (ATD) treatment. Thyrotropin (TSH) receptor antibodies (TRAb) cause Graves' disease. Thyroid-stimulating antibody (TSAb) and TSH-binding inhibitor immunoglobulin (TBII) have been measured as TRAb to diagnose Graves' disease and to follow Graves' patients. Smooth decreases of TSAb and TBII during ATD treatment predict the remission of Graves' hyperthyroidism. We followed serial changes of TSAb and TBII in 58 Graves' patients before, during, and after ATD treatment; TSAb was measured as a stimulator assay, using porcine thyroid cells, and TBII as a receptor assay. Patterns of TSAb and TBII changes during ATD treatment differ from one patient to another. TSAb and TBII activities decreased and disappeared in 52 (group A) but continued to be high in the other 6 (group B); 39 of the 52 group A patients achieved remission, but all of the 6 group B patients with persistently positive TSAb and TBII continued to have hyperthyroidism. No differences in the initial TSAb and TBII activities were noted between the 52 group A patients and the 6 group B patients. Of the 52 group A patients in whom TSAb and TBII had disappeared, 44 had smooth decreases of TSAb and TBII (group A1), and 8 had complex changes of TSAb and/or TBII (group A2); 36 of the 44 group A1 patients (82%) but only 3 of the 8 group A2 patients (37%) continued to be in remission more than 1 year after ATD discontinuation. The number of remission in group A1 was significantly larger than that in group A2. No differences in the initial TSAb and TBII activities were noted between group A1 and group A2. More than 80% of group A1 patients, who had smooth decreases of TSAb and TBII, continued to be in remission longer than 1 year. We demonstrated that smooth decreases of TSAb and TBII during ATD treatment predicted the remission of Graves' hyperthyroidism. The Graves' patients can be classified into A1, A2, and B groups according to the patterns of TSAb and TBII changes during ATD treatment. Group A1 patients, who had smooth decreases of TSAb and TBII, had higher rate of remission than the others. Smooth decreases of TSAb and TBII during the early phase of ATD treatment are a reliable predictor of the remission.

Sensitive thyroid-stimulating antibody assay in whole serum containing five percent polyethylene glycol using porcine thyroid cells

Previously we reported that the amounts of cyclic adenosine monophosphate (cAMP) production by polyethylene glycol (PEG) 22.5% precipitated fraction (PF) (crude immunoglobulin G [IgG]) from thyroid-stimulating antibody (TSAb)-positive serum were higher than those by PEG 12.5% PF, and that PEG (5%) augmented affinity purified TSAb-IgG-stimulated cAMP production in porcine thyroid cells (PTC) assay. In the present work, we studied sensitive TSAb assay using whole sera in the presence of high PEG concentrations in PTC assay. cAMP produced by TSAb-positive serum increased in proportion to serum amounts up to 0.05 mL, but gradually decreased in 0.075 mL. The maximal augmentative effect of PEG on TSAb-positive serum (0.05 mL)-stimulated cAMP production was found in 5% PEG (final). Thus, TSAb assay using whole serum (0.05 mL) in the absence of 5% PEG (serum method) and sensitive TSAb (sTSAb) assay using whole serum (0.05 mL) in the presence of 5% PEG (serum plus 5% PEG method) were performed. The sensitive thyroid-stimulating antibody (sTSAb) activities of Graves' sera showed significantly higher (twofold to sevenfold) compared to simple TSAb activity with sera. sTSAb and TSAb activities were positive in 91% (29/32) and 47% (15/32) of untreated Graves' patients with hyperthyroidism. The sTSAb activities by serum plus 5% PEG method were higher than that by PEG 12.5% precipitated fraction (PF) from test serum (0.2 mL) in many Graves' sera, but lower than that by PEG 22.5% PF from test serum (0.2 mL). PEG (5%) did not augment cAMP produced by high TSH serum (127-210 mU/L) in thyroiditis chronica. sTSAb activity was negative in adenomatous goiter, subacute thyroiditis, and thyroid cancer. sTSAb activity was also negative in TSH stimulation blocking antibody (TSBAb)-positive hypothyroidism (during thyroxine [T4] treatment), but was positive in Graves' sera with coexistence serum of TSAb and TSBAb because of augmentative effect of 5% PEG on TSAb activity. This assay in whole serum (0.05 mL) containing 5% PEG is less sensitive than sensitive TSAb assay using PEG 22.5% PF from test serum (0.2 mL), but this method can be available clinically as routine TSAb assay using whole serum because of the technical simplicity.

Localization of oxidized HDL in atheromatous plaques and oxidized HDL binding sites on human aortic endothelial cells

We examined the localization of oxidized high-density lipoprotein (HDL) in atheromatous plaques and the oxidized HDL binding sites on endothelial cells. Histochemical analysis using CuSO4-oxidized HDL-specific 9F5-3a antibody indicated the presence of oxidized HDL in the intima of atheromatous plaques in human abdominal aortae. The cell surface binding of 125I-oxidized HDL to cultured human aortic endothelial cells (HAEC) was saturable, with an apparent dissociation constant (Kd) of 1.43 micromol/L. Competition for 125I-oxidized HDL binding was strong for oxidized HDL, moderate for native HDL and low for acetylated low-density lipoprotein (LDL) or oxidized LDL. Using oxidized HDL as a ligand for blotting, a major 130-kDa band was detected in HAEC. These results suggest that oxidized HDL and its putative binding protein are present in atheromatous plaques and endothelial cells, respectively.

The effect of ketamine isomers on both mice behavioral responses and c-Fos expression in the posterior cingulate and retrosplenial cortices

Ketamine, a non-competitive NMDA receptor antagonist, is a racemic mixture. S(+) ketamine is presumed to be more potent as an anesthetic than R(-) ketamine, and causes less postanesthetic stimulation of locomotor activity than R(-) ketamine in animals at equihypnotic doses. In the present study, we investigated the effect of S(+), R(-), and racemic ketamines on mice behavioral responses and c-Fos expression in the posterior cingulate and retrosplenial cortices (PC/RS), which are suggested to be the brain regions responsible for NMDA-receptor-antagonist-induced psychotomimetic activity. Ataxia and head weaving and c-Fos expression in the PC/RS were significantly more induced by both S(+) and racemic ketamines than by R(-) ketamine at the same dose. S(+) ketamine induced significantly more potent ataxia than racemic ketamine at the same dose. Ketamine-induced c-Fos expression in the PC/RS correlated well with the intensity of behavioral responses. These results imply that R(-) ketamine is weaker than both S(+) and racemic ketamines in a psychotomimetic effect. Also, S(+) ketamine is more potent than racemic ketamine in a psychotomimetic effect and possibly in an anesthetic effect. They also indicate that PC/RS is at least one of the specific brain regions responsible for ketamine-induced behavioral responses in animals and a psychotomimetic activity in humans.

Electroencephalographic arousal response during tracheal intubation and laryngeal mask airway insertion after induction of anaesthesia with propofol

Laryngoscopy and tracheal intubation, or insertion of a laryngeal mask airway may lead to an arousal response on the electroencephalogram. We studied whether more intense stimulation (laryngoscopy and tracheal intubation) causes a greater arousal response than less intense stimulation (laryngeal mask airway insertion). Thirty-four patients (ASA I-II) were anaesthetised with propofol 3 mg.kg-1, followed by vecuronium 0.15 mg.kg-1 and a propofol infusion of 10 mg.kg-1.h-1. Three minutes after induction of anaesthesia, either laryngoscopy and tracheal intubation (n = 18), or laryngeal mask airway insertion (n = 16) was performed. Laryngoscopy and tracheal intubation caused a significantly greater increase in blood pressure (but not heart rate) than laryngeal mask airway insertion (p < 0.05). Electroencephalogram responses were not different. More intense stimulation does not cause a greater arousal response during propofol anaesthesia.