Effect of acid suppressant medications on the laxative action of magnesium preparations in patients with opioid-induced constipation: A pharmacovigilance analysis of the FDA Adverse Event Reporting System

Objective: Magnesium oxide is widely used for treating opioid-induced constipation, a serious analgesic-associated problem. Opioid analgesic users are often prescribed non-steroidal anti-inflammatory drugs, which are sometimes combined with acid suppressants to prevent gastrointestinal adverse events. Magnesium preparations combined with acid suppressants may diminish magnesium preparations' laxative effect. This study was aimed at evaluating the effect of magnesium preparations combined with acid suppressants on the incidence of opioid-induced constipation by using the Food and Drug Administration Adverse Event Reporting System. Methods: Adverse events were defined per the Medical Dictionary for Regulatory Activities; the term 'constipation (preferred term code: 10010774)' was used for analysis. After adjusting for patient background factors using propensity score matching, acid suppressants' effect on constipation incidence was evaluated in opioid users prescribed magnesium preparations alone as laxatives by using a test for independence. Key Findings: The Food and Drug Administration Adverse Event Reporting System contains 14,475,614 reports for January 2004 to December 2021. Significantly increased constipation incidence was related to magnesium preparations combined with acid suppressants, especially proton pump inhibitors (P < 0.0001, McNemar's test). Conclusion: Magnesium preparations combined with acid suppressants may diminish magnesium preparations' laxative effect; healthcare professionals should pay attention to this issue.

Investigating the activation of passive metals by a combined in-situ AFM and Raman spectroscopy system: a focus on titanium

Understanding the main steps involved in the activation of passive metals is an extremely important subject in the mechanical and energy industry and generally in surface science. The titanium-H₂SO₄ system is particularly useful for this purpose, as the metal can either passivate or corrode depending on potential. Although several studies tried to hypothesise the surface state of the electrode, there is no general consensus about the surface state of Ti in the active-passive transition region. Here by combining in-situ atomic force microscopy (AFM) and Raman spectroscopy, operating in an electrochemical cell, we show that the cathodic electrification of Ti electrodes causes the dissolution of the upper TiO₂ portion of the passive film leaving the electrode covered by only a thin layer of titanium monoxide. Fast anodic reactions involved the acidification of the solution and accumulation of sulphur containing anions. This produces a local increase of the solution turbidity, allowing to distinguish favourable regions for the precipitation of TiOSO₄·2H₂O. These results give a clear answer to the long-stated question of the physical origin behind the formation of negative polarization resistances, sometimes occurring in corroding systems, and a rationale about the proton-induced degradation of passive surfaces in presence of sulphur containing species.

Correlation and Linear Regression between Blood Pressure Decreases after a Test Dose Injection of Propofol and that following Anaesthesia Induction

Propofol reduces systemic vascular resistance and suppresses cardiac function when injected rapidly. In this study we investigated whether blood pressure decrease after a minimal dose (test-dose) injection of propofol correlates with that after an induction-dose injection.

Patients were randomly divided into two groups; anaesthesia was induced in group A (n=60) using 1.5 mg/kg propofol and in group B (n=61) using 2.0 mg/kg. Blood pressure reduction after a minimal dose injection (0.4 mg/kg) was examined non-invasively prior to anaesthetic induction. Bispectral Index monitoring was measured and sedation level scored to evaluate anaesthetic depth.

After the minimal dose injection, 18 of 121 patients showed behaviour suggesting minor disinhibition, five patients were sedated and seven were drowsy. Oxygen saturation was not significantly changed after test-dose injection. Reduction in systolic blood pressure (mean±SD) was 17±11 mmHg after the minimal dose injection, 42±20 mmHg after a 1.5 mg/kg induction dose injection, and 42±22 mmHg after a 2.0 mg/kg induction-dose injection. In both groups, blood pressure after induction was significantly lower than the control value (P<0.05). In both groups, a positive correlation was observed between blood pressure reduction after the minimal dose injection and that after the induction-dose injection [P<0.01, R value for systolic blood pressure correlation in group A 0.712 (P<0.01) and in group B 0.758 (P<0.01)].

We concluded there was a positive correlation between blood pressure reduction after a minimal (test-dose) injection and that after an induction-dose injection.

Is the Degree of Sensitivity to Nondepolarizing Muscle Relaxants Related to Requirements for Postoperative Ventilation in Patients with Myasthenia Gravis?

The purpose of this study was to examine whether the degree of sensitivity to nondepolarizing muscle relaxants is related to the requirement for postoperative ventilatory support in patients with myasthenia gravis.

Thirty-six patients with myasthenia gravis undergoing trans-sternal thymectomy were monitored by electromyography in order to assess the neuromuscular response to vecuronium. After calibration to 100% of baseline electromyographic response values using an EMG monitor, incremental doses of 5, 10 and 20 μg/kg of vecuronium were administrated to produce 95% neuromuscular blockade and to obtain a cumulative dose-response curve for each patient. A univariable logistic regression with odds ratio was used to examine the predictive variables of prolonged postoperative ventilation. Depending on their postoperative ventilatory needs, patients were divided into an early extubation group and a prolonged ventilatory group.

There were no significant differences between the two groups in terms of vecuronium ED95 (prolonged ventilation group: 23.2±18 μg/kg; early extubation group: 23.2±18 μg/kg, P=0.129) and vecuronium requirement to maintain less than 25% neuromuscular blockade (prolonged ventilation group: 2.4±1.7 mg/kg; early extubation group: 3.8±4.5 mg/kg, P=0.249). There were, however, significant differences in the incidence of a history of previous respiratory crises and the presence of bulbar palsy between the early extubation and prolonged ventilation groups. History of previous respiratory crisis (odds ratio (OR), 3.5; 95% confidence interval (CI), 1.0-13; P=0.03) and presence of bulbar palsy (OR, 3.7; 95%CI, 0.9-15; P=0.049) were associated with the need for prolonged postoperative ventilation. However, we failed to demonstrate that the degree of sensitivity to nondepolarizing muscle relaxants was related to an increased requirement for postoperative ventilation in patients with myasthenia gravis.

Hypertonic saline for intraoperative fluid therapy in transurethral resection of the prostate

We tested hypertonic saline solution (HS) to determine its effectiveness in surgical procedures for prostatic hypertrophy. We randomly selected 40 patients undergoing elective transurethral resection of the prostate for either infusion of HS (3% NaCl) at 4ml·kg(-1)·min(-1) (HS group) or lactated Ringer's solution (LR) at 8 ml·kg(-1)·min(-1) (LR group). Anesthesiologists regulated the intraoperative infusion rate as needed to maintain blood pressure. There were no differences in systolic blood pressure, heart rate, central venous pressure, or arterial blood oxygenation between the two groups. In the HS group, plasma sodium, chloride, and osmolality, measured in the recovery room, were significantly increased; however, they returned to preanesthetic levels the day after surgery. In the LR group, in contrast, plasma sodium decreased significantly and this lower value persisted for 1 day. An osmolar gap exceeding 10mOsm·kg(-1) was observed in 2 patients in the HS group, but plasma sodium remained at normal values. However, in the 1 patient in the LR group whose osmolar gap exceeded 10mOsm·kg(-1), plasma sodium was 115 mEq·I(-1). HS, at a low dose, is useful in the intraoperative management of transurethral resection of the prostate.

The effects of isoflurane on adrenomedullin-induced haemodynamic responses in pithed rats

BACKGROUND AND OBJECTIVES

Adrenomedullin is a potent vasodilatory peptide. The mechanisms of adrenomedullin-induced responses are via guanine nucleotide guanosine 5'-triphosphate-binding protein (G-protein)-coupled receptor activation and are similar to those of calcitonin gene-related peptide (CGRP). Previously, we reported that sevoflurane and isoflurane inhibit CGRP-induced haemodynamic responses. The effects of volatile anaesthetics on adrenomedullin-induced haemodynamic responses, however, are unclear. We hypothesized that the volatile anaesthetic isoflurane inhibits adrenomedullin-induced haemodynamic responses. We studied the effects of isoflurane on adrenomedullin-induced haemodynamic responses in pithed rats, which enables us to evaluate the direct cardiovascular effects of drugs without interference from centrally mediated circulatory reflexes.

METHODS

Male Wistar rats were pithed by inserting a stainless-steel rod into the spinal cord. Following median sternotomy, a flow probe was placed around the ascending aorta to measure aortic blood flow. Mean arterial pressure and cardiac output were maintained at approximately 100 mmHg and 50 mL min-1, respectively, with continuous infusion of norepinephrine. After 30 min inhalation of isoflurane (1%, or 2%) in oxygen, or only oxygen, adrenomedullin (1, 3, 10 or 30 microg kg-1) was administered intravenously.

RESULTS

Adrenomedullin administration induced a transient increase followed by a persistent decrease in mean arterial pressure and cardiac output. Isoflurane (2%) significantly inhibited the initial increase in mean arterial pressure and the later decrease in mean arterial pressure and systemic vascular resistance.

CONCLUSION

Isoflurane inhibits adrenomedullin-induced vasodilation and positive inotropic effect in pithed rats. Isoflurane might inhibit the adrenomedullin receptor-mediated response, which is a common pathway for both actions.

Percutaneous radio-frequency mandibular nerve rhizotomy guided by CT fluoroscopy

We describe a new method for radio-frequency mandibular nerve rhizotomy under CT fluoroscopy. A patient with cancer had severe intractable and drug-resistant pain in his left mandibular region. Because he had an anatomic deformity due to cancer invasion and radiation therapy, we planned a mandibular nerve rhizotomy under CT fluoroscopic imaging. The needle was advanced to the mandibular nerve just caudal to the foramen ovale under real-time CT fluoroscopy, avoiding the cancer region. Pain scores of the patient were reduced after the nerve rhizotomy, without any complications.

Changes in the effect of propofol in response to altered plasma protein binding during normothermic cardiopulmonary bypass

BACKGROUND

During normothermic cardiopulmonary bypass (CPB), the effect on propofol pharmacokinetics of changes in its binding to plasma proteins is consistent with the predictions of the well-stirred model of hepatic elimination for nonrestrictively cleared drug. However, whether changes in binding lead to clinically significant changes in the drug effect remains unclear. The purpose of this study was to assess changes in the drug effect of propofol in response to altered plasma binding using quantitative EEG measurements.

METHODS

Thirty patients undergoing cardiac surgery were assigned randomly to receive propofol infusions at 4 (Group P-4) or 6 (Group P-6) mg kg(-1) h(-1) during surgery. The concentration of propofol in blood samples, collected from the radial artery at predetermined intervals, was determined by HPLC. The unbound fraction of drug in plasma was estimated using equilibrium dialysis. Bispectral index (BIS) and burst suppression ratio (BSR) were measured at the time blood samples were collected.

RESULTS

The total concentration of propofol in blood was unchanged during CPB relative to the pre-CPB value in both groups. However, the fraction of unbound propofol in blood increased by 2-fold during CPB. While BIS values were unchanged during CPB in Group P-4, there was a slight, but significant, decrease in Group P-6. In both groups, BSR significantly increased during CPB. BIS values showed a weak correlation with the concentration of unbound propofol (r(2)=0.19, P<0.001). BSR showed a moderate correlation with the concentration of unbound propofol (r(2)=0.56, P<0.001).

CONCLUSIONS

The anaesthetic effect of propofol significantly increased during CPB without any alteration in the total drug concentration. The enhanced efficacy may be caused by a reduction in plasma binding of the drug.

Changes in apparent systemic clearance of propofol during transplantation of living related donor liver

BACKGROUND

Propofol is used during living-related donor liver transplantation because its metabolism is not greatly affected by liver failure. However, the pharmacokinetics of propofol during liver transplantation have not been fully defined. The purpose of this study was to evaluate the apparent systemic clearance of propofol during the dissection, anhepatic and reperfusion phases of living-related donor liver transplantation, and to estimate the role of the small intestine and lung as extrahepatic sites for propofol disposition.

METHODS

Ten patients scheduled for living-related donor liver transplantation were enrolled in the study. Anaesthesia was induced with vecuronium 0.1 mg kg(-1) and propofol 2 mg kg(-1), and then maintained by 60% air, 0.5-1.5% isoflurane in oxygen and a constant infusion of propofol at 2 mg kg(-1) h(-1). Apparent systemic clearance during the dissection, anhepatic and reperfusion phases was calculated from the pseudo-steady-state concentration for each phase. Disposition in the small intestine was determined by measuring arteriovenous blood concentration in 10 liver transplantation donors. Pulmonary disposition was determined by measuring the arteriovenous blood concentration in 10 recipients during the anhepatic phase. The data are expressed as mean (sd).

RESULTS

Apparent systemic clearances in the dissection, anhepatic and reperfusion phases were 1.89 (sd 0.48) litre min(-1), 1.08 (0.25) litre min(-1) and 1.53 (0.51) litre min(-1), respectively. The concentration of propofol in the portal vein was lower than in the radial artery. The intestinal extraction ratio calculated from the concentration in the radial artery and portal vein was 0.24 (0.12). There were no significant differences in propofol concentrations between the radial and pulmonary arteries.

CONCLUSION

Apparent systemic clearance was decreased by approximately 42 (10)% during the anhepatic phase compared with the dissection phase. After reperfusion, liver allografts rapidly began to metabolize propofol. The small intestine also participates in the metabolism of propofol.

Effects of AM281, a cannabinoid antagonist, on systemic haemodynamics, internal carotid artery blood flow and mortality in septic shock in rats

INTRODUCTION

The purpose of this study was to examine the effects of AM281, a cannabinoid receptor antagonist, on systemic haemodynamics, internal carotid artery blood flow and mortality during septic shock in rats.

METHODS

The study included three sets of experiments: measurements of changes in systemic haemodynamics and left internal carotid artery flow (30 animals divided into three groups of 10); measurements of biochemical variables (n=30); assessment of mortality (n=30). Male Wistar rats (7 weeks old) were randomly divided into three groups: group 1, control; group 2, lipopolysaccharide (LPS) i.v., Escherichia coli endotoxin 10.0 mg kg(-1) i.v., bolus; group 3, LPS 10.0 mg kg(-1) i.v.+AM281 1 mg kg(-1) i.v. Systemic haemodynamics, carotid artery flow changes and biochemical variables were assessed at pretreatment and 1, 2 and 3 h after the treatment was performed.

RESULTS

Administration of AM281 could prevent the haemodynamic changes induced by sepsis. Tumour necrosis factor-alpha and interleukin 1-beta increased in the LPS i.v. and LPS i.v.+AM281 groups at 1, 2 and 3 h after treatment; significant differences were observed in these levels in the two groups at these times. Internal carotid artery blood flow remained fairly constant in the control and LPS i.v.+AM281 groups compared with baseline values. In the LPS i.v. group, it decreased at 2 and 3 h after the treatment compared with baseline values [at 2 h: control 12.7 (SD 0.9) ml min(-1), LPS i.v. 8.7 (1.4) ml min(-1) (P<0.05), LPS i.v.+AM281 11.5 (0.9) ml min(-1); at 3 h: control 12.7 (0.4) ml min(-1), LPS i.v. 7.7 (1.3) ml min(-1) (P<0.05), LPS i.v.+AM281 11.6 (1.0) ml min(-1)]. Significant differences in mortality within 6 and 12 h were found between the LPS i.v. and LPS i.v.+AM281 groups [6 h mortality: LPS i.v. 5/10 (50%), LPS i.v.+AM281 2/10 (20%), P<0.05; 12 h mortality: LPS i.v. group 10/10 (100%), LPS i.v.+AM281 5/10 (50%), P<0.05].

CONCLUSIONS

Administration of AM281 prevented changes in systemic haemodynamic and internal carotid artery blood flow and could improve mortality in experimentally induced septic shock in rats. These findings may have significant therapeutic implications in the treatment of septic shock.

Calcium entry blocker nicardipine inhibits sodium and inorganic phosphate reabsorption independent of renal circulation in dogs

The effects of nicardipine on renal function were studied in anesthetized dogs. The changes in the tubular sodium (Na) and inorganic phosphate (PO(4)) reabsorption caused by the drug infusion into the renal artery without altered systemic and real circulation were especially evaluated. In dogs receiving a smaller dose of nicardipine (5 ng.kg(-1).min(-1)) into the left renal artery the blood pressure and renal circulation did not change, but urine volume and urinary Na and PO(4) excretion increased significantly. In dogs receiving a larger dose of nicardipine (50 ng.kg(-1).min(-1)) into the renal artery, renal plasma flow, urine volume and urinary Na and PO(4) excretion increased significantly, but creatinine clearance did not. The fractional distal Na reabsorption did not change with nicardipine infusion in either group. PO(4) reabsorption is considered to occur mainly in the proximal renal tubule, so its appearance in urine in increased quantities without the changes of systemic and renal circulation suggests proximal activity of the drug.

Slow rewarming improves jugular venous oxygen saturation during rewarming

BACKGROUND

There have been many studies regarding the etiology of postoperative cognitive dysfunction after coronary artery bypass graft (CABG) surgery. Although its etiology remains unresolved, one possible factor related to postoperative cognitive dysfunction is a reduced internal jugular venous oxygen hemoglobin saturation (SjvO2) during the rewarming period. The purpose of this study was to examine the effect of rewarming rates on SjvO2 during rewarming.

METHODS

One-hundred patients scheduled for elective CABG surgery were randomly divided into two groups; control group (0.48 +/- 0.09 degrees C, n = 50), slow rewarming group (0.24 +/- 0.09 degrees C, n = 50). After the induction of anesthesia, a fiberoptic oximetry oxygen saturation catheter was inserted into the right jugular bulb to monitor SjvO2 continuously. Hemodynamic parameters, arterial and jugular venous blood gases were measured at nine time-points.

RESULTS

Cerebral desaturation (defined as a SjvO2 value below 50%) during rewarming was more frequent in the control group than in the slow group. Cerebral desaturation time (duration when SjvO2 was less than 50%) and the ratio of the cerebral desaturation time to the total CPB time in the control group differed significantly from those in the slow group (control group: 17 +/- 11 min, 12 +/- 4%, slow group: 10 +/- 8 min, 7 +/- 4%, respectively, P < 0.05). There was no significant difference in mini-mental state examination on the day before the operation nor at 1 month after the surgery among four values (the day before the operation: control group; 48 +/- 8, slow group; 48 +/- 7, at one month after the surgery: control group; 46 +/- 7, slow group; 45 +/- 9).

CONCLUSIONS

A slow rewarming rate could reduce the chance of a decrease in SjvO2 during rewarming.

The comparative effects of propofol versus thiopentone on left ventricular function during electroconvulsive therapy

The purpose of this study was to compare the effect of propofol versus thiopentone on haemodynamics during electroconvulsive therapy (ECT), as estimated by echocardiography. Twenty-eight ASA 1 or 2 patients scheduled for ECT were randomly divided into two groups, to receive propofol 1 mg/kg (propofol group, n = 14) or thiopentone 2 mg/kg (thiopentone group, n = 14). Bilateral ECT was performed after the administration of propofol or thiopentone, succinylcholine and following assisted mask ventilation with 100% oxygen. Cardiac function was examined by transthoracic echocardiography, prior to induction of anaesthesia and throughout ECT until ten minutes after the seizure. In the propofol group, increased end-systolic area (ESA) and decreased fractional area change (FAC) were observed at one minute after the electrical shock compared with the awake condition. In the thiopentone group, increased ESA and decreased FAC were observed from one to three minutes after the electrical shock compared with the awake condition. There was no statistically significant change in afterload in the propofol group during the study. In contrast, increased afterload was observed from one to three minutes after the electrical shock in the thiopentone group (awake condition, 26 +/- 7 mmHg/cm2 [mean +/- SD]; one minute after ECT, 42 +/- 7*; two minutes after ECT, 44 +/- 6*; three minutes after ECT; 40 +/- 5*, respectively) (*P < 0.05). We concluded that a lesser haemodynamic change occurs after propofol anaesthesia (1 mg/kg) compared with thiopentone anaesthesia (2 mg/kg) during ECT.

Chronic intraperitoneal endotoxin treatment in rats induces resistance to d-tubocurarine, but does not produce up-regulation of acetylcholine receptors

BACKGROUND

Chronic systemic inflammation resulting from intraperitoneal Eschevichia coli endotoxin administration or Corynebacterium injections induces tolerance to non-depolarizing neuromuscular blockers in rodents. Although this has been explained as up-regulation of muscle acetylcholine receptors (AChR), the numbers of involved receptors have not been documented. The aim of this study was to determine the effects of chronic endotoxin administration on rat muscle AChR.

METHODS

One day after one, seven, or 14 daily intraperitoneal doses of lipopolysaccharide endotoxin (0 or 0.5 mg kg(-1)), we studied in vivo dose-response relationships for d-tubocurarine (d-Tc) and AChR binding using [125I]alpha-bungarotoxin as a ligand.

RESULTS

One day after seven and 14 daily intraperitoneal doses of endotoxin, the effective dose of d-Tc required to suppress the twitch response to 50% of the control (ED50) was significantly increased compared with that of time-matched control rats (146.5 +/- 38.2 vs. 76.1 +/- 9.0 microg kg(-1) for seven doses; 116.4 +/- 51.3 vs. 74.4 +/- 9.6 micro g kg-1 for 14 doses, P < 0.05). However, this was not associated with an increase in the number of AChR in the anterior tibial muscle or diaphragm.

CONCLUSIONS

Mechanisms other than AChR up-regulation might be responsible for the increased d-Tc requirement during chronic intraperitoneal endotoxin administration.

Patterns of canal and otolith afferent input convergence in frog second-order vestibular neurons

Second-order vestibular neurons (2 degrees VN) were identified in the isolated frog brain by the presence of monosynaptic excitatory postsynaptic potentials (EPSPs) after separate electrical stimulation of individual vestibular nerve branches. Combinations of one macular and the three semicircular canal nerve branches or combinations of two macular nerve branches were stimulated separately in different sets of experiments. Monosynaptic EPSPs evoked from the utricle or from the lagena converged with monosynaptic EPSPs from one of the three semicircular canal organs in ~30% of 2 degrees VN. Utricular afferent signals converged predominantly with horizontal canal afferent signals (74%), and lagenar afferent signals converged with anterior vertical (63%) or posterior vertical (37%) but not with horizontal canal afferent signals. This convergence pattern correlates with the coactivation of particular combinations of canal and otolith organs during natural head movements. A convergence of afferent saccular and canal signals was restricted to very few 2 degrees VN (3%). In contrast to the considerable number of 2 degrees VN that received an afferent input from the utricle or the lagena as well as from one of the three canal nerves (~30%), smaller numbers of 2 degrees VN (14% of each type of 2 degrees otolith or 2 degrees canal neuron) received an afferent input from only one particular otolith organ or from only one particular semicircular canal organ. Even fewer 2 degrees VN received an afferent input from more than one semicircular canal or from more than one otolith nerve (~7% each). Among 2 degrees VN with afferent inputs from more than one otolith nerve, an afferent saccular nerve input was particularly rare (4-5%). The restricted convergence of afferent saccular inputs with other afferent otolith or canal inputs as well as the termination pattern of saccular afferent fibers are compatible with a substrate vibration sensitivity of this otolith organ in frog. The ascending and/or descending projections of identified 2 degrees VN were determined by the presence of antidromic spikes. 2 degrees VN mediating afferent utricular and/or semicircular canal nerve signals had ascending and/or descending axons. 2 degrees VN mediating afferent lagenar or saccular nerve signals had descending but no ascending axons. The latter result is consistent with the absence of short-latency macular signals on extraocular motoneurons during vertical linear acceleration. Comparison of data from frog and cat demonstrated the presence of a similar organization pattern of maculo- and canal-ocular reflexes in both species.

High-concentration tetracaine for the management of trigeminal neuralgia: quantitative assessment of sensory function after peripheral nerve block

OBJECTIVE

This study examined the effects of peripheral nerve block with high-concentration tetracaine for the management of trigeminal neuralgia, and evaluated sensory function by measuring the postblock current perception threshold.

METHODS

Five infraorbital nerve blocks were performed in five elderly patients using 4% tetracaine dissolved in saline or 0.5% bupivacaine. The authors used a neurometer to compare postblock current perception threshold between the block side and the contralateral healthy side, and used cold tests to assess the sensory level.

RESULTS

The analgesic effect of tetracaine blocks continued for a median period of 2 months (range, 1.5-months). Hypesthesia was observed in all patients after the block but resolved within a mean period of 2.2 weeks. Although differences in current perception threshold values between sides were not significant in any patient, block-side values in two patients were clinically higher than contralateral-side values (250 vs. 5 Hz) for some time before returning to normal levels.

CONCLUSION

Peripheral nerve block with high-concentration tetracaine is a relatively safe and useful technique in the management of trigeminal neuralgia, particularly among older patients and those with systemic problems.

N-methyl-D-aspartate receptor-dependent and -independent cytotoxic effects of Dictyostelium discoideum differentiation-inducing factor-1 on rat cortical neurons

Differentiation-inducing factor-1 (DIF-1) is a chlorinated alkylphenone (small lipophilic hormone) that induces stalk cell formation in the cellular slime mold Dictyostelium discoideum. Recent studies have revealed that DIF-1 inhibits growth and induces the differentiation of mammalian tumor cells. The present study examines the effects of DIF-1 on rat cortical neurons in primary culture. We found that DIF-1 induced rapid neuronal cell death. The release of lactate dehydrogenase (LDH), as an indicator of cell death, increased dose-dependently with DIF-1. The release of LDH was inhibited by the N-methyl-D-aspartate (NMDA) receptor antagonists MK801 and AP5, suggesting that the NMDA receptor is involved in the induction of cell death by DIF-1. However, glutamate cytotoxicity could not explain the entire action of DIF-1 on neurons because the estimated concentration of glutamate around DIF-1-treated neurons was below 50 microM and DIF-1 caused more severe cell death than 500 microM glutamate. We discovered that another portion of DIF-1 cytotoxicity is independent of the NMDA receptor; that is, coaddition of DIF-1 and MK801 induced dendritic beading and increased expression of the immediate early genes c-fos and zif/268. These results indicate that DIF-1 induces rapid cell death via both NMDA receptor-dependent and -independent pathways in rat cortical neurons.

Sevoflurane and nitrous oxide anaesthesia suppresses heart rate variabilities during deliberate hypotension

BACKGROUND AND OBJECTIVE

Despite the fact that both general anaesthetics and hypotensive drugs influence autonomic nervous activity, no study has yet examined the heart rate variability during deliberate hypotension and general anaesthesia. The aim of this was to clarify the heart rate variability changes during deliberate hypotension under sevoflurane-nitrous oxide anaesthesia.

METHODS

Autonomic nervous system activity in patients (n=45) subjected to deliberate hypotension during sevoflurane in nitrous oxide and oxygen anaesthesia was investigated by a heart rate variability measurement. Three different types of hypotensive drugs, a calcium channel antagonist (nicardipine), a nitric oxide donor (nitroglycerin) and a vasodilatory prostaglandin (alprostadil), were used to induce hypotension.

RESULTS

In all groups, low frequency power (sympathetic and parasympathetic indicator) and the ratio of low frequency to high frequency power (the LF/HF ratio, sympathetic indicator) were suppressed by induction of anaesthesia. In the control group, preanaesthesia low frequency power was 195 +/- 139 ms(2), the LF/HF ratio 10.3 +/- 5.7, during anaesthesia 5 +/- 9 ms(2), 0.6 +/- 0.8, respectively, P=0.0093, 0.0034, whereas high frequency power (parasympathetic indicator) was not significantly changed. In those patients receiving nicardipine or nitroglycerin during anaesthesia, these variables did not differ significantly from those in the control group. During prostaglandin E1 infusion, high frequency power was higher compared with the values in the other groups (17 +/- 12 ms(2) in the prostaglandin group, 7 +/- 6 ms(2) in the nicardipine group, 6 +/- 5 ms(2) in the nitroglycerin group and 6 +/- 4 ms(2) in the control group, respectively, P=0.0326, 0.0251, 0.0197).

CONCLUSIONS

Sevoflurane in nitrous oxide and oxygen anaesthesia reduces sympathetic autonomic activity considerably, and the expected increases caused by hypotensive agents that occur in awake volunteers were not seen.

Disturbances in hepatocellular function during cardiopulmonary bypass using propofol anaesthesia

BACKGROUND AND OBJECTIVE

Serum hyaluronate is thought to be an indicator of derangement in hepatocellular integrity, and the change in serum hyaluronate is a useful indicator in various liver disorders. We assessed the changes in serum hyaluronate in patients undergoing coronary artery bypass graft surgery.

METHODS

Eleven patients scheduled for elective coronary artery bypass graft surgery were studied. An oximetry oxygen saturation catheter was inserted into the right hepatic vein to permit monitoring of hepatic venous oxygen saturation. Perioperative measurements included: haemodynamic variables; systemic oxygen delivery and uptake; arterial, mixed venous and hepatic venous oxygen saturation; arterial and hepatic venous plasma concentrations of lactate, arterial ketone body ratio (ratio of acetoacetate to 3-hydroxybutyrate); and arterial and hepatic venous hyaluronate were measured.

RESULTS

Arterial and hepatic venous hyaluronate increased during cardiopulmonary bypass compared with the prebypass period. These increases returned to prebypass values after the cessation of bypass (hepatic venous hyaluronate value at the prebypass period: 26 +/- 13 ng mL(-1), during bypass: 77 +/- 40 ng mL(-1); 1 h after bypass: 57 +/- 42 ng mL(-1); 6 h after bypass: 32 +/- 15 ng L(-1), 24 h after bypass; 62 +/- 21 ng mL(-1); mean +/- SD, P < 0.05). The arterial and hepatic venous hyaluronate during cardiopulmonary bypass was correlated with total bilirubin and hepatic venous lactate concentrations 6 h after bypass (arterial hyaluronate at cardiopulmonary bypass period vs. total bilirubin at 6 h after bypass; r=0.793, P=0.0036, hepatic venous hyaluronate during bypass vs. that at 6 h after bypass; r=0.795, P=0.0035).

CONCLUSIONS

Hepatocellular integrity might be disturbed during cardiopulmonary bypass when propofol anaesthesia is used.

Decrease in jugular venous oxygen saturation during normothermic cardiopulmonary bypass predicts short-term postoperative neurologic dysfunction in elderly patients

OBJECTIVES

We sought to examine whether the decrease in jugular venous oxygen saturation (SjvO(2)) during cardiopulmonary bypass (CPB) can be used to predict short-term and long-term postoperative cognitive disorders in elderly patients.

BACKGROUND

It has been reported that elderly patients might be more susceptible to hypoperfusion during CPB.

METHODS

One hundred eighty-five patients scheduled for elective coronary artery bypass graft surgery were studied. Group 1 (n = 56) was young (<50 years old), group 2 (n = 67) was middle-aged (50 to 69 years old) and group 3 (n = 62) was elderly (>70 years old). After induction of anesthesia, a fiberoptic oximetry oxygen saturation catheter was inserted into the right jugular bulb to monitor SjvO(2) continuously. Hemodynamic variables and arterial and jugular venous blood gases were measured at seven time points.

RESULTS

The cerebral desaturation time (duration when SjvO(2) was <50%) and the ratio of the cerebral desaturation time to the total CPB time in group 3 were significantly different from those in groups 1 and 2 (group 1: 20 +/- 6 min and 16 +/- 5%; group 2: 19 +/- 7 min and 14 +/- 6%; group 3: 34 +/- 9 min and 24 +/- 7%, respectively; p < 0.05). Also, age (odds ratio [OR] 1.3, 95% confidence interval [CI] 1.0 to 1.8, p = 0.02) and desaturation time (OR 1.3, 95% CI 1.0 to 1.4, p = 0.03) were perioperative factors in relation to short-term cognitive impairment. However, age and desaturation time were not perioperative factors in relation to long-term cognitive impairment.

CONCLUSIONS

Reduced SjvO(2) was associated with short-term cognitive dysfunction in elderly patients.

Hepatosplanchnic oxygenation is better preserved during mild hypothermic than during normothermic cardiopulmonary bypass

PURPOSE

To assess and compare the effects of normothermic and mild hypothermic cardiopulmonary bypass (CPB) on hepatosplanchnic oxygenation.

METHODS

We studied 14 patients scheduled for elective coronary artery bypass graft surgery who underwent normothermic (>35 degrees C; group I, n=7) or mild hypothermic (32 degrees C; group II, n=7) CPB. After induction of anesthesia, a hepatic venous catheter was inserted into the right hepatic vein to monitor hepatic venous oxygen saturation (ShvO(2)) and hepatosplanchnic blood flow by a constant infusion technique that uses indocyanine green.

RESULTS

The ShvO(2) decreased from a baseline value in both groups during CPB and was significantly lower at ten minutes and 60 min after the onset of CPB in group I (39.5 +/- 16.2% and 40.1 +/- 9.8%, respectively) than in group II (61.1 +/- 16.2% and 61.0 +/- 17.9%, respectively; P <0.05). During CPB, the hepatosplanchnic oxygen extraction ratio was significantly higher in group I than in group II (44.0 +/- 7.2% vs 28.7 +/- 13.1%; P <0.05).

CONCLUSION

Hepatosplanchnic oxygenation was better preserved during mild hypothermic CPB than during normothermic CPB.

Direct neurotoxicity of tetracaine on growth cones and neurites of growing neurons in vitro

BACKGROUND

Local anesthetics have direct neurotoxicity on neurons. However, precise morphologic changes induced by the direct application of local anesthetics to neurons have not yet been fully understood. Also, despite the fact that local anesthetics are sometimes applied to the sites where peripheral nerves may be regenerating after injury, the effects of local anesthetics on growing or regenerating neurons have never been studied.

METHODS

Three different neuronal tissues (dorsal root ganglion, retinal ganglion cell layer, and sympathetic ganglion chain) were isolated from an age-matched chick embryo and cultured for 20 h. Effects of tetracaine were examined microscopically and by a quantitative morphologic assay, growth cone collapse assay.

RESULTS

Tetracaine induced growth cone collapse and neurite destruction. Three neuronal tissues showed significantly different dose-response, both at 60 min and at 24 h after the application of tetracaine (P < 0.01). The ED50 values (mean +/- SD) at 60 min were 1.53+/-1.05 mM in dorsal root ganglion, 0.15+/-0.05 mM in retinal, and 0.06+/-0.02 mM in sympathetic ganglion chain cultures. The ED50 values at 24 h were 0.43+/-0.15 mM in dorsal root ganglion, 0.07+/-0.03 mM in retinal, and 0.02+/-0.01 mM in sympathetic ganglion chain cultures. Concentration of nerve growth factor in the culture media did not influence the ED50 values. The growth cone collapsing effect was partially reversible in dorsal root ganglion and retinal neurons. However, in the sympathetic ganglion culture, no reversibility was observed after exposure to 1 mM tetracaine for 10 or for 60 min. Bupivacaine had similar neurotoxicity to the three types of growing neurons. (The ED50 values at 60 min were 2.32+/-0.50 mM in dorsal root ganglion, 0.96+/-0.16 mM in retinal, and 0.18+/-0.05 mM in sympathetic ganglion chain cultures. The ED50 values at 24 h were 0.34+/-0.09 mM in dorsal root ganglion, 0.21+/-0.06 mM in retinal, and 0.45+/-0.10 mM in sympathetic ganglion chain cultures.)

CONCLUSIONS

Short-term exposure to tetracaine produced irreversible changes in growing neurons. Growth cones were quickly affected, and neurites degenerated subsequently. Sensitivity varied with neuronal type and was not influenced by the concentration of nerve growth factor. Because a similar phenomenon was observed after exposure to bupivacaine, the toxicity to growing neurons may not be unique to tetracaine.

Hydrothorax: an unexpected complication after laparoscopic myomectomy

We report a case of hydrothorax as a complication of laparoscopic myomectomy in an otherwise healthy woman. The most likely cause of the patient's hydrothorax was irrigation fluid moving from the peritoneal cavity into the pleural space via defects in the diaphragm. Anaesthesists and surgeons should consider hydrothorax as a potential complication in any patient undergoing laparoscopy.

Effects of small doses of prostaglandin E(1) on systemic hemodynamics and jugular venous oxygen saturation during cardiopulmonary bypass

STUDY OBJECTIVE

To examine the effects of small doses of prostaglandin E(1) (PGE(1)) on systemic hemodynamics and cerebral oxygenation during cardiopulmonary bypass(CPB).

DESIGN

Randomized, prospective study.

SETTING

Cardiac surgery at Saitama Cardiovascular and Pulmonary Center.

PATIENTS

Forty patients who underwent elective coronary artery bypass surgery.

INTERVENTIONS

The study was performed at the stable CPB period. Patients were randomly divided into four groups: control group (n = 10) received an infusion of saline, PGE(1) 10 group (n = 10) received an infusion of PGE(1) 10 ng/kg/min, PGE(1) 25 group (n = 10) received an infusion of PGE(1) 25 ng/kg/min, and the PGE(1) 50 group (n = 10) received an infusion of PGE(1) 50 ng/kg/min.

MEASUREMENTS

After measuring the baseline partial pressure of the arterial oxygen saturation (SpO(2)), mixed venous oxygen saturation (SvO(2)), and jugular venous oxygen saturation (SjvO(2)), blood gases, and cardiovascular hemodynamic values, PGE(1) was infused intravenously at rate of between 10 and 50 ng/kg/min. PGE(1) infusion continued 30 minutes after the start of drug infusion, and the blood gas analysis and cardiovascular hemodynamic values were simultaneously determined together with the hemodynamic values at 2, 5, 10, 20, and 30 minutes during drug infusion. At 30 minutes after discontinuation of the drug infusion, the blood gas analyses were simultaneously determined together with the hemodynamic values.

MAIN RESULTS

Mean arterial pressure (MAP) in PGE(1) 25 and 50 groups was decreased 20 and 30 minutes after the start of PGE(1) infusion compared with the baseline value (p < 0.05). In contrast, SvOm(2) in PGE(1) 25 and 50 groups was increased 20 and 30 minutes after the start of PGE(1) infusion compared with the baseline value (p < 0.05). There was no change in SjO(2) value despite a decrease in MAP during the study.

CONCLUSIONS

Cerebral oxygenation estimated by SjvO(2) was maintained despite a decrease in MAP during the administration rate of PGE(1) between 10 and 50 ng/kg/min.

Time course of changes in jugular venous oxygen saturation during hypothermic or normothermic cardiopulmonary bypass in patients with diabetes mellitus

BACKGROUND

Preexisting diabetic mellitus is a risk factor determining postoperative neurological disorders. The present study assesses the effects of normothermic and hypothermic cardiopulmonary bypass (CPB) on jugular venous oxygen saturation (SjvO2)in patients with preexisting diabetic mellitus.

METHODS

Sixteen diabetic patients who underwent elective coronary artery bypass grafting surgery were randomly divided into two groups: Group DN (n=8, diabetic patients) underwent normothermic CPB (>35 degrees C), and group DH (n=8, diabetic patients) underwent hypothermic CPB (32 degrees C). Controls were 16 age-matched non-diabetic patients (normothemic group, CN: n=8; hypothemic group, CH: n=8). A 4.0 F fiberoptic oximetry oxygen saturation catheter was inserted into the right jugular bulb to continuously monitor SjvO2 values. Hemodynamic parameters and arterial and jugular venous blood gases were measured seven times.

RESULTS

Cerebral desaturation, which was defined as SjvO2 values below 50%, was observed during normothermic CPB in diabetic patients (at the onset of CPB: 46+/-3%, at 20 min after onset of CPB: 49+/-3%, means+/-SD, respectively). No cerebral desaturation occurred in diabetic and control patients during hypothermic CPB.

CONCLUSIONS

Patients with preexisting diabetes mellitus experienced cerebral desaturation during normothermic CPB.

Effects of 5-HT2 and 5-HT3 receptors on the modulation of nociceptive transmission in rat spinal cord according to the formalin test

We used the formalin test to clarify the 5-hydroxytryptamine (5-HT) receptor subtypes involved in the modulation of spinal nociceptive transmission in rats. Intrathecal administration of a 5-HT1A receptor agonist, 8-hydroxy-2-(di-n-propylamino)-tetraline (8-OH-DPAT; 1, 10, and 30 microg), or a 5-HT1B receptor agonist, 1, 4-dihydro-3-(1, 2, 3, 6-tetrahydro-4-pyridinyl)-5H-pyrrol (3, 2-b) pyridin-5-one (CP 93129; 1 and 10 microg), produced no significant change in the number of flinches. A 5-HT(2) receptor agonist, (+/-)-2, 5-dimethoxy-4-iodoamphetamine (DOI; 10, 30, and 100 microg), and a 5-HT3 receptor agonist, 2-methyl-5-HT (100 and 300 microg), produced dose-dependent decreases in the number of flinches in phases 1 (1 to 6 min) and 2 (10 to 61 min) of the test. The antinociceptive effects of DOI and 2-methyl-5-HT were antagonized by intrathecal pretreatment with a 5-HT2 receptor antagonist, ketanserin, and a 5-HT3 receptor antagonist, 3-tropanyl-3, 5-dichlorobenzoate (MDL-72222), respectively. These results suggest that 5-HT2 and 5-HT3 receptors in the spinal cord mediate antinociception to chemical stimuli.

The expression of a barley HvNAS1 nicotianamine synthase gene promoter-gus fusion gene in transgenic tobacco is induced by Fe-deficiency in roots

Nicotianamine (NA) is a precursor for mugineic acid-family phytosiderophores, which are a critical component of the Fe aquisition process in graminaceous plants. In addition, nicotianamine synthase (NAS) is strongly induced in these plants by Fe deficiency. NA is essential for Fe metabolism also in dicots, but NAS is not induced by Fe deficiency. We introduced a barley HvNAS1 promoter-gus fusion gene into tobacco. GUS activity was induced in the roots of these plants by Fe deficiency, and was constitutively expressed at a low level in their leaves.

A rat model of postthoracotomy pain: behavioural and spinal cord NK-1 receptor assessment

PURPOSE

To develop a new rat model of postthoracotomy pain for investigating its mechanisms and clarifying neurochemical changes.

METHODS

Male Wistar rats were randomly assigned to three groups that underwent either fourth and fifth intercostal nerve ligation, cutting of the fourth and fifth ribs, or a sham operation in which only pleura was cut. For behavioural response assessment during the following month, pinch and touch were used as mechanical stimuli, and acetone was used as a cold thermal stimulus. In addition, (125)I-substance P autoradiography was used to determine neurokinin (NK) receptor density in spinal cord laminae I and II at one to six weeks after surgery.

RESULTS

In rats with nerve ligation, hypersensitivity to noxious and non-noxious stimuli continued throughout the month. The "mirror phenomenon" was observed. The lowest threshold was obtained in the dorsomedial portion of the T4 dermatome on the side of surgery. In rats with rib cutting, a lowered threshold to noxious and non-noxious stimuli was observed for two weeks. In rats with sham operations, hypersensitivity was seen only at postoperative day one. NK-1 receptor density on the side of operation increased significantly in rats with nerve ligation from day seven to 28. Receptor density was highest on day 14 (22.97 +/- 1.04 fmol x mg(-1) tissue vs. control, 16.22 +/- 0.43), representing a 50% receptor excess on the side of ligation compared to the contralateral side.

CONCLUSION

Intercostal nerve damage induces long-term postthoracotomy pain and an increase of spinal NK-1 receptors in rats. This model may be useful for investigation of postthoracotomy pain.

A novel plant ferritin subunit from soybean that is related to a mechanism in iron release

Ferritin is a multimeric iron storage protein composed of 24 subunits. Ferritin purified from dried soybean seed resolves into two peptides of 26.5 and 28 kDa. To date, the 26.5-kDa subunit has been supposed to be generated from the 28-kDa subunit by cleavage of the N-terminal region. We performed amino acid sequence analysis of the 28-kDa subunit and found that it had a different sequence from the 26.5-kDa subunit, thus rendering it novel among known soybean ferritins. We cloned a cDNA encoding this novel subunit from 10-day-old seedlings, each of which contained developed bifoliates, an epicotyl and a terminal bud. The 26.5-kDa subunit was found to be identical to that identified previously lacking the C-terminal 16 residues that correspond to the E helix of mammalian ferritin. However, the corresponding region in the 28-kDa soybean ferritin subunit identified in this study was not susceptible to cleavage. We present evidence that the two different ferritin subunits in soybean dry seeds show differential sensitivity to protease digestions and that the novel, uncleaved 28-kDa ferritin subunit appears to stabilize the ferritin shell by co-existing with the cleaved 26.5-kDa subunit. These data demonstrate that soybean ferritin is composed of at least two different subunits, which have cooperative functional roles in soybean seeds.

Postlesional vestibular reorganization in frogs: evidence for a basic reaction pattern after nerve injury

Nerve injury induces a reorganization of subcortical and cortical sensory or motor maps in mammals. A similar process, vestibular plasticity 2 mo after unilateral section of the ramus anterior of N. VIII was examined in this study in adult frogs. The brain was isolated with the branches of both N. VIII attached. Monosynaptic afferent responses were recorded in the vestibular nuclei on the operated side following ipsilateral electric stimulation either of the sectioned ramus anterior of N. VIII or of the intact posterior vertical canal nerve. Excitatory and inhibitory commissural responses were evoked by separate stimulation of each of the contralateral canal nerves in second-order vestibular neurons. The afferent and commissural responses of posterior vertical canal neurons recorded on the operated side were not altered. However, posterior canal-related afferent inputs had expanded onto part of the deprived ramus anterior neurons. Inhibitory commissural responses evoked from canal nerves on the intact side were detected in significantly fewer deprived ramus anterior neurons than in controls, but excitatory commissural inputs from the three contralateral canal nerves had expanded. This reactivation might facilitate the survival of deprived neurons and reduce the asymmetry in bilateral resting activities but implies a deterioration of the original spatial response tuning. Extensive similarities at the synaptic and network level were noted between this vestibular reorganization and the postlesional cortical and subcortical reorganization of sensory representations in mammals. We therefore suggest that nerve injury activates a fundamental neural reaction pattern that is common between sensory modalities and vertebrate species.

Perioperative management of biventricular failure after closure of a long-standing massive arteriovenous fistula

PURPOSE

To report the perioperative management of arteriovenous fistula (AVF) closure in a patient with high-output heart failure and pulmonary hypertension.

CLINICAL FEATURES

In a 71-yr-old man, closure of a long-standing massive AVF between the right femoral artery and vein was performed. After closure of the AVF, his pulmonary artery pressure (PAP) increased from 52/21 mmHg to 68/26 mmHg, his cardiac index decreased from 5.27 L.min(-1).m(-2) to 3.18 L.min(-1).m(-2), and his pulmonary wedge pressure increased from 15 mmHg to 32 mmHg due to an acute increase in afterload. Co-administration of prostaglandin E and a phosphodiesterase III inhibitor improved the cardiac index and the PAP.

CONCLUSIONS

Surgical closure of the fistula may not always lead to resolution of the high output cardiac failure. In this case, afterload management using arterial dilators (prostaglandin E1, phosphodiesterase III inhibitor), use of inotropic drugs (phosphodiesterase III inhibitor), and close attention to volume status was crucial for a successful outcome after surgical AVF closure.

[Successful management of a patient who developed intra-operative pulmonary tumor embolism]

A 68-year-old female with retroperitoneal tumor extending into the inferior vena cava (IVC) developed massive pulmonary tumor embolism during removal of the tumor. Because of her unstable hemodynamics, emergency pulmonary embolectomy under cardiopulmonary bypass was performed. Successful management of her intra- and post-operative persistent right heart failure led to a satisfactory postoperative course without serious neurological complications. In peri-operative management of a patient with an extended tumor into IVC, prevention of the embolism, detection of the pulmonary embolism and treatment of intra- and post-operative right heart failure are important.

Arytenoid dislocation while using a McCoy laryngoscope

Arytenoid dislocation (AD) involves either a complete disruption of the cricoarytenoid joint or a malpositioning of the arytenoid cartilages (AC) with reference to other laryngeal cartilages. In this report, we present a case of AD while using a McCoy laryngoscope. Although McCoy laryngoscope is recognized as a useful option for the cases of difficult endotracheal intubation, we are concerned that AD is likely with this device.

Electroconvulsive therapy impairs systolic performance of the left ventricle

PURPOSE

In this observational study, we examined left ventricular systolic performance during electroconvulsive therapy (ECT), using an echocardiographic automated border detection system.

METHODS

Nine ASA I or II patients scheduled for ECT were studied. Bilateral ECT was performed after the administration of propofol 1 mg x kg(-1), succinylcholine 1 mg x kg(-1), and assisted mask ventilation with 100% oxygen. Cardiac function was monitored by transthoracic echocardiography, prior to anesthesia induction and throughout the ECT procedure until ten minutes after the seizure.

RESULTS

Increased end-systolic area and decreased fractional area change were observed at one minute after the seizure compared to the awake condition. No regional wall motion abnormalities were observed in all patients both at baseline condition and during the ECT CONCLUSION: Systolic performance of the left ventricle estimated by echocardiography decreased transiently in the immediate period after the electric shock.

Application of ion beam techniques for preparation of metal ion-implanted TiO2 thin film photocatalyst available under visible light irradiation: metal ion-implantation and ionized cluster beam method

Transparent TiO2 thin film photocatalysts have been prepared on silica glass plate by an Ionized Cluster Beam (ICB) method. In order to improve the electronic properties of these photocatalysts, transition metal ions (V+, Cr+, Mn+, Fe+) were implanted into the TiO2 thin films at high energy acceleration using an advanced metal ion-implantation technique. The combination of these ion beam techniques can allow us to prepare the TiO2 thin film photocatalysts which can work effectively under visible light (lambda>450 nm) and/or solar light irradiation. The investigation using XAFS and ab initio molecular calculation suggests that the substitution of octahedrally coordinated Ti ions in TiO2 lattice with implanted metal ions is important to modify TiO2 to be able to adsorb visible light and operate under visible light irradiation.

Antiallodynic effect of intrathecally administered 5-HT(2) agonists in rats with nerve ligation

We examined the antiallodynic effect of intrathecally administered serotonin receptor agonists including 5-HT(1A), 5-HT(1B), 5-HT(2) and 5-HT(3) receptor subtypes in a rat model using spinal nerve ligation at L5 and L6. Administration of the 5-HT(2) receptor agonist, alpha-methyl-5-hydroxytryptamine maleate (alpha-m-5-HT; 3-100 microg) or (+/-)-1-(4-iodo-2,5-dimethoxyphenyl)-2-aminopropane hydrochloride (DOI; 10-100 microg), showed dose-dependent antiallodynic actions with no associated motor weakness. The antiallodynic action of alpha-m-5-HT was more potent than that of DOI. The effects of 5-HT(2) agonists on tactile allodynia were reversed by intrathecal pretreatment with the selective 5-HT(2) antagonist ketanserin and with the mixed 5-HT(1) and 5-HT(2) antagonist methysergide. Neither the mixed 5-HT(1A) and 5-HT(1B) antagonist cyanopindolol nor the selective 5-HT(3) antagonist MDL72222 attenuated antiallodynic effects induced by 5-HT(2) agonists. In contrast, the selective 5-HT(1A) agonist 8-hydroxy-2-(di-n-propylamino)-tetralin hydrobromide (8-OH-DPAT; 1-50 microg), the 5-HT(1B) agonist 5-methoxy-3-(1,2,5,6-tetrahydro-4-pyridinil)-1H-indol (RU-24969; 10-100 microg) and the 5-HT(3) agonist 2-methyl-5-hydroxytryptamine maleate (2-m-5-HT; 30-300 microg) all lacked significant antiallodynic action with intrathecal administration. These results indicate that the 5-HT(2) receptor plays an essential role in spinal suppression of neuropathic pain by 5-HT.

Perilymph fistula--45 case analysis

PURPOSE OF THE STUDY

Though perilymph fistula (PLF) is not a rare disease, preoperative diagnosis still remains to be established. Some new diagnostic methods are challenging, but there is still no established diagnostic method except exploratory tympanotomy that verifies the occurrence of leakage. Early diagnosis of PLF is fully depending on history taking and some clinical examinations. To know the clinical features of PLF is one of the greatest helps to make both earlier and accurate diagnosis. In spite of some innovations in clinical examinations classic diagnostic procedure is thought to be still reliable.

PROCEDURES

We investigated the clinical symptoms, basic tests results and therapeutic results in patients with PLF.

RESULTS

From 1983 to 1998 PLF was identified in 44 patients (45 ears) with exploratory tympanotomies in our hospital. With respect to clinical history the predisposing factors such as blowing the nose, lifting heavy goods, and landing in an airplane were found in almost half of the patients, while the rest of them had no clear inducing factors. Their major symptoms included hearing loss (93%), vertigo and dizziness (91%), tinnitus (76%), and aural fullness (31%). The patients who have a clear predisposing factor tended to make diagnosis easily; on the other hand the rest of the patients who do not have clear etiology had some diagnostic difficulty. Subjective positive fistula signs were observed in 71% of patients. Vestibular symptoms improved in 80% of patients after closure of PLF.

CONCLUSIONS

These results suggest that the variety of clinical manifestation make diagnosis more difficult. At the moment meticulous clinical history taking and close follow-up applying repeating fistula tests are the most important for not only earlier but also accurate diagnosis.

The comparative effects of propofol versus thiopental on middle cerebral artery blood flow velocity during electroconvulsive therapy

Electroconvulsive therapy provokes abrupt changes in both systemic and cerebral hemodynamics. An anesthetic that has a minor effect on cerebral hemodynamics might be more suitable for patients with intracranial complications, such as cerebral aneurysm. The purpose of our present study was to compare the effects of thiopental and propofol on cerebral blood flow velocity. We continuously compared cerebral blood flow velocity at the middle cerebral artery (MCA) during electroconvulsive therapy, using propofol (1 mg/kg, n = 20) versus thiopental (2 mg/kg, n = 20) anesthesia. Systemic hemodynamic variables and flow velocity at the MCA were measured until 10 min after the electrical shock. Heart rate and arterial blood pressure increased in the thiopental group until 5 min after the electrical shock. In the propofol group, an increase in mean blood pressure was observed to 1 min after the electrical shock. Mean flow velocity at the MCA decreased after anesthesia in both groups, and increased at 0.5-3 min after the electrical shock in the thiopental group and at 0.5 and 1 min after the shock in the propofol group. The flow velocities at 0.5-5 min after the electrical shock were significantly more rapid in the thiopental group compared with the propofol group. ¿abs¿

IMPLICATIONS

Cerebral blood flow velocity change, measured by transcranial Doppler sonography during electroconvulsive therapy, was minor using propofol anesthesia compared with barbiturate anesthesia. Propofol anesthesia may be suitable for patients who cannot tolerate abrupt cerebral hemodynamic change.

Use of a fibreoptic stylet to visually evaluate tracheal intubation technique

To compare the tracheal intubation by novices with that of instructors, we videotaped the view obtained through a fibreoptic stylet during standard tracheal intubations with a Macintosh direct laryngoscope. The duration of visualization of the vocal cords was longer during intubation by instructors than during trainee attempts. The tracheal tube contact (with pharyngeal wall) time duration was higher during intubation attempts by trainees than instructors. The quality of the image of the vocal cords through the stylet was related to these video-view parameters. Our results demonstrated that visualization of the vocal cords by direct laryngoscope and manipulation of the tracheal tube in the oral cavity were different between anaesthesia trainees and instructors, and suggested that visually monitoring the tracheal intubation procedure through a fibreoptic stylet might be useful for the education of anaesthesia trainees.

Antinociception in rat by sarpogrelate, a selective 5-HT(2A) receptor antagonist, is peripheral

The antinociceptive effect of sarpogrelate, a new selective 5-hydroxytriptamine (5-HT)(2A) receptor antagonist, in the formalin test was examined in rats. Sarpogrelate was administered intraperitoneally, locally (subcutaneously at the formalin test site) or intrathecally 10 min before formalin injection. Intraperitoneal (1-100 mg/kg) and local (0.01-1 mg) administration of sarpogrelate suppressed flinching behavior in both phases 1 (0-9 min) and 2 (10-60 min) in a dose-dependent manner. Intraperitoneal (100 mg/kg) and local (1 mg) injection 7 min after formalin injection reduced phase 2 flinches to the same degree as with the pre-treatment. Intrathecal administration (1-100 microg) showed no antinociceptive action, and facilitated phase 2 flinches at 10 microg. The plasma concentration of sarpogrelate after local administration of 1 mg was lower than after intraperitoneal administration of 10 mg/kg, although local administration produced more potent antinociception. The data imply that the antinociceptive effect of sarpogrelate results mainly from an action at peripheral sites.

Reduction of cerebral hyperemia with anti-hypertensive medication after electroconvulsive therapy

PURPOSE

Several different anti-hypertensive regimens have been introduced for the prevention of systemic hyperdynamic responses after electrically induced seizures. In the present study, the effects of anti-hypertensive medications on cerebral circulation were studied.

METHODS

Systemic blood pressure was controlled by several anti-hypertensive medications, nicardipine, prostaglandin EI, alprenolol and nitroglycerin, in 30 patients (150 electroconvulsive therapy trials). Changes in cerebral blood flow velocity were measured by transcranial Doppler sonography of the right middle cerebral artery from the start of anesthesia to 10 min after the electrical shock.

RESULTS

Administration of a Ca2+ antagonist, nicardipine, or prostaglandin EI did not alter the augmented cerebral blood flow velocity after the seizure. However, a beta-adrenergic blocking agent, alprenolol (P<0.05) or nitroglycerin (P<0.01) partially inhibited the increase in cerebral blood flow velocity. Maximal blood flow velocity was 133% larger than the pre-anesthesia value in the control group, 109% in the nicardipine group, 113% in the prostaglandin EI group, 72% in the alprenolol group, and 45% in the nitroglycerin group, respectively. The increase in cerebral blood flow velocity after electrically induced seizure was independent of systemic blood pressure. Internal jugular venous saturation (SjO2) was increased, and difference in arterial and venous concentrations of lactate was not altered in all groups.

CONCLUSIONS

Cerebral hemodynamics is altered by ECT, even when systemic hemodynamics are stabilized by antihypertensive medication. Although the effects of antihypertensive medicine on cerebral hemodynamics are variable, systemic blood pressure control by these agents does not induce cerebral ischemia after ECT.

Creutzfelt-Jakob disease presenting hyperparathyroidism

We reported a 68-year-old female with Creutzfelt-Jakob disease (CJD) presenting hyperparathyroidism. She was suspected as Creutzfelt-Jakob like syndrome at her initial visit to our hospital because of progressive dementia and high level of serum calcium. Finally she was diagnosed as having CJD by the clinical symptoms including progressive dementia and myoclonus and the characteristic patterns of brain CT and electroencephalogram (EEG). CJD presents a variety of symptoms including progressive dementia, apathy and myoclonus. Hyperparathyroidism and toxicity of lithium, delirium and bismuth have been reported to induce similar symptoms of CJD, which are called Creutzfelt-Jakob like syndrome. Therefore, the diagnosis of CJD would be difficult in cases with CJD accompanied with Creutzfelt-Jakob like syndrome. It is rare for otolaryngologists to examine patients with dementia like CJD. However, we have to keep CJD in mind in the diagnosis of hyperparathyroidism.

Expansion of afferent vestibular signals after the section of one of the vestibular nerve branches

The anterior branch of N. VIII was sectioned in adult frogs. Two months later the brain was isolated to record in vitro responses in the vestibular nuclei and from the abducens nerves following electric stimulation of the anterior branch of N. VIII or of the posterior canal nerve. Extra- and intracellularly recorded responses from the intact and operated side were compared with responses from controls. Major changes were detected on the operated side: the amplitudes of posterior canal nerve evoked field potentials were enlarged, the number of vestibular neurons with a monosynaptic input from the posterior canal nerve had increased, and posterior canal nerve stimulation recruited stronger abducens nerve responses on the intact side than vice versa. Changes in the convergence pattern of vestibular nerve afferent inputs on the operated side strongly suggest the expansion of posterior canal-related afferent inputs onto part of those vestibular neurons that were deprived of their afferent vestibular input. As a mechanism we suggest reactive synaptogenesis between intact posterior canal afferent fibers and vestibularly deprived second-order vestibular neurons.